$ Building a Slant 6 for performance

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Palmetto

Palmetto

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I was told that it costs more to build up a Slant 6 for performance than a 318. Have any of your guys verified this? I am intriqued by what guys are doing with their slants. Amazing performance out of this bullet proof motor.
I have seen some very cool looking slant 6 engines on this site.
 
Probably about the same. I just assembled my 318 and am piecing together my slant. They are close in price.
 
I appreciate the /6 for what it is, one of the most durable engines ever & guys on here do some really cool stuff with them. However, I've come to realize that it takes a lot of money having someone else do the machine work necessary to get a /6 much more HP. Shaving the head, if not the block too raising the compression, & putting in oversize valves. Besides your usual bolt on mods, like a 4 barrel, Offy or Clifford Header etc. Unless you Super/Turbocharge.
Not that re-sale value should be a very top priority in this hobby but it's good to realize if you decide to go V-8 after you've spent $1,000+?? or more on the /6, it's still probably not likely to fetch $200. Fewer interested buyers=lower demand= lower price. Sure, you could show some receipts, but it's still a hard sell. There is kind of a stigma attached unfortunately. For example you could start at 220 HP with a 90s Magnum 318 (for about $300 around here) and go up from there HP wise, instead of spending a ton of money on the six. However you would have to get a 318 727 trans, and 8 1/4 or expensive 8 3/4 rear end. That's probably $600-$1,000 maybe. A few trade offs. To each his own. My 198 /6 is still stock at this point, I've picked up on great info thanks to this great forum.
 
Elwood67 said:
Shaving the head, if not the block too raising the compression, & putting in oversize valves. Besides your usual bolt on mods, like a 4 barrel, Offy or Clifford Header etc.
Click to expand...

Sounds a lot like V8 mods. So, what's the difference?
 
Palmetto said:
I was told that it costs more to build up a Slant 6 for performance than a 318. Have any of your guys verified this? I am intriqued by what guys are doing with their slants. Amazing performance out of this bullet proof motor.
I have seen some very cool looking slant 6 engines on this site.
Click to expand...

If you can stay awake for all this, here is a comparison I wrote awhile back for a ball-park cost-analyis for going with a turbo225 and a small block of equal power.

YMMV...



Comparison of turbo Slant Six 500 HP build vs. 500 HP 318/340/360 small block build





The following is written in reference to the 225 motor. The 170 is a different kettle of fish.


It would seem that slant 6 motors (remember, this is a 225 thread) were built (though, not intentionally,) to be force-fed air and fuel.
Whether it's done with a supercharger, nitrous oxide, or a turbo, it once-and-for-all, makes an end run around the built-in breathing problem that slant sixes suffer from birth. Because of their small bores, they can never have the kind of breathing that will deliver horsepower in the 1.75 hp-per-cubic-inch range. Not with that original, cast-iron, 2-valve head, at least.

The engine is rpm limited because of the long (4-1/8") stroke, so it's never going to deliver the goods at 8,000 rpm. That's the rpm where most small-block Chevys that are really "built" seem to make big power. I'm talking the small-displacement, short stroke models.

RPM? Forget it.

Because of the fact that the original plans for the slant 6 included an aluminum block (and, the fact tht that aluminum isn't as strong as cast iron,) the basic specifications for the slant 6 block were robust, to say the least; they had to be... aluminum needs more mass and are to be as strong as it needs to be for reliability, than cast iron. Well, the engine that went on to live in Mopars of various descriptions for many years, turned out to be cast iron.

But, the changes in the cast iron version, from the aluminum parameters, were minimal.

That meant that the resulting engine was an unusually strong critter, not unlike a Diesel, in basic construction.

A forged steel crank with mains the size of a 426 Hemi’s made for an equally-strong bottom end.

Along the way, someone a whole lot smarter than I am, realized that what this all meant was, you could boost the s**t out of this little motor without hurting it. Boost = performance increases!

Tom Wolfe and Ryan Peterson built the prototypes for the engine that is in the '64 Valiant that Freddie and I plan to run. We bald-facedly copied their lead, and we are HOPEFULLY going to run within a second of their cars. There are only minimal differences in their "recipe" from ours. But, they did it first; we're just copy-cats.


In this diatribe, I am going to try to justify why anyone would want to go this route, ($$$$$$$$$$$,) and perhaps point out a few reasons why it might not be such a good idea, after all...


There are (at least) two kinds of people out there; those who just want to go fast, and those who want to go fast and prove something in the process.

Anybody can stick a big engine into a light car with easily predictable results: It's gonna be F-A-S-T!!! Those 440+ cubic inch A Bodies are hard to outrun... and, with good reason! Ma made it pretty easy to drop an RB engine into an A-Body, and beyond getting it to hook, the problems in getting it to go fast are not actually what you'd call "insurmountable." Whoever said, "There's no substitute for cubic inches," said a mouthful!

Senor' Schumacher has made the task of installing a big engine into a Dart or Duster a lot easier, with his motor mounts and custom-fit big-engine-in-a-in small car headers. The appeal is almost overwhelming, if you love "speed."

Some folks, though, look at that operation and say, "Ho Hum... It SHOULD be fast; big block in a small car.... so what?"

Some of those detractors want to produce a fun car with a smaller engine, but not TOO small.. There are the 318/340/360 guys who don't want the hassles that go with the installation of a third-member-breaking big block, but would still like to trim a few Corvettes.

To them, a small-block is the answer; they don't want to mess with a slant six, because 1. They don't like the way they sound, and 2. it's hard to build one that will outrun most Corvettes. They probably have never SEEN an 11-second slant six car. Or, a 12-second one; thirteen second slant six cars are not even that plentiful.... so, they know that they can stick a set of headers on a 340, raise the compression to 11.5:1, go with any one of a hundred different solid lifter cams, and presto," a low 12-second car that will embarrass most street driven anything, Corvettes, included.

Enter the slant 6 turbo, the type of engine that most regular-guy Mopar enthusiasts think is an oddball, weird combination that yeah, may be pretty fast, but has to be expensive!!! Right? I mean, you don't get 2+ horsepower per cubic inch out of a slant six without a ton of costly, cutting-edge technology!

Well, that's just not true.

Let me point out what ~I~ have found out about this turbo six business that has made me wonder whether it might not be actually CHEAPER than building an equal-power small block. Especially, if you already HAVE the /6, but will have to buy a V8.


Here are a few ways that the turbo slant six can be a cheaper alternative to an equally-powerful small block.

For purposes of comparison, let's compare two 500 horsepower engines; one normally-aspirated 360, with time-honored, normal hop-up mods to produce 500 flywheel HP and a turbocharged slant six with equal power.


Lets start with acquiring a rebuildable engine "core."

People give away slant 6's all the time. The one we are attempting to build was, in fact, given to us. It was on its way to the dump, if we didn’t want it. “Free” is always good…

That scenario is also possible with small blocks, but not as easy... and virtually impossible to find a "free" rebuildable 340. But, you don't HAVE to start with a 340; it can even be a 318... but that won’t be as easy. A 500-horsepower 318 is not hard to imagine, but probably would need some pretty good heads, and 12-1 compression. It would also need to be rpm capable, to a large degree. (7,000?)

Not so hard with a 360, but they are not as much in abundance for free, I think. Could be wrong about that. More like $150 for a rebuildable "core."

Advantage, slant 6.

There is more of everything to buy for 8 cylinders compared with 6. Pistons, valves, bearings, rings, valve springs... retainers, keepers...

Advantage, slant 6

The driveability of a turbo slant 6 is not much different from a stocker, in that the main thing(s) that destroy driveability, are radical cams with a fast, ragged idle, and big ports that allow the fuel to fall out of suspension (at low rpm) in the ports, due to low velocities brought on by the size of the ports. The turbo slant six cams don't have much more duration than a stock one, and the ports, even in ported heads, aren't very big.

Advantage, slant 6.

The slant six's that have been turbocharged with high-boost (over 20 pounds,) don't seem to like rpm's and don't NEED rpm's to deliver the goods. Tom Wolfe and Ryan Peterson, the two examples I am citing here, both contend that their engines have a de-facto red line of about 5,500 rpm. With such a low red line, the reciprocating stresses, even with a 1-and-an-eithth-inch, stroke, are low enough that these engines will never fail due to bearing loads brought on by excessive piston speed, That is MY opinion; nothing more. Making 500 horsepower from a normally-aspirated small block is going to require that you spin it, probably fast enough to put engine life in jeopardy, if you do it very often.

Advantage, slant six (my opinion)

Because of the relatively low rpm operation of the turbo slant six, the valve train can remain, with stock pushrods and rocker arms, due to the low valve spring pressures required. The money you DON'T have to spend on needle bearing, rollerized rockers, special, heavy-duty pushrods and roller lifters is money saved.

Advantage, slant six.

The rear axle ratios in the two quickest A Body turbo slant six cars that I have seen evidence of, are 2.76:1 for the strip AND for the street. The turbo motors are weird, in that the car slows down with normally-"steep" rear gears, such as the 4.56:1 units often found in small-block cars. The turbo motor seems to make more power (not unlike a "fuel" motor) when it is "held back" and not allowed to increase rpm quickly. The significance if this is, the turbo motors also can use the same ratio for highway driving AND drag strip action. The small block "built" motor wouldn't think much of a 2.76:1 rear end on the drag strip, nor would it perform up to its potential, with a 4.56:1 on the highway. So, if you build a small block and it does double duty, you really need two sets of gears; one for the drag strip and one of the highway. No problem; you can change third members in a couple of hours (or, less.) But, they don't give away 8.75" A-Body housings these days, and neither is it cheap to buy and maintain two sets of third members, with different ratios; one for racing, blah, blah, blah...

The turbo slant six car can easily make do with a "one-ratio-fits-all" rear end. A late model, A Body 8.25" rear end from a junk yard will be lots cheaper (or, one out of an Aspen/Volare car) and will come with highway (and drag strip) gears already in it.... and is plenty strong for this application. More money saved.

Advantage, slant six

Because a high-stall converter is neither desirable nor necessary, turbo slant six converters are going to be cheaper than a 4,000-5,000-rpm unit that would be probably necessary for a wildly-cammed small block. Once again, the street driveability issue comes to light. The tighter slant six converter would not create as much heat as a high-stall, small block unit would, in daily driving.

Advantage, slant six

I BELIEVE that a turbocharged slant six motor is about 80-100 pounds
lighter than an iron small block. Can't prove that, but I'd bet on it.

Advantage slant six

The "bling" factor at shows might be of interest to some. A nice-looking small block has a LOT of competition at car shows and usually needs to have something really special, in cosmetic appeal, to win an award, just because there are so many... But, a slant six with a turbo on it is such a rarity, judges HAVE to pay attention.

Advantage, slant six

Then, there are the negative factors... and, there are some!

You can always put a turbo on a small block and go much faster than you could EVER hope to go with a slant six


Advantage, small block

No roller cams are available for slant six engine (no available roller-tappet cores) so, the ZDDP issue is always a problem.

Advantage, small block

You REALLY need both an intercooler AND a chemical intercooler (alcohol injector) for a hi-boost turbo slant six, and they don't give these away. None is needed on a normally-aspirated small block,

Advantage, small block

I don't think that a turbocharged slant six is a very good bracket car for drag racing, because of problems with turbo-spool on takeoff, and consistency. We are not building our car to run brackets; if we wanted to win bracket races, we'd build something else.

Advantage; small block

Detonation under boost will destroy a turbocharged motor on boost, quicker than you can say "turbo." So, fuel of sufficient octane is always going to be a problem. E-85 would be the perfect hi-octane fuel, but the quality of it at the pump is so iffy, you just can't trust it when it comes to boosted motors. The normally-aspirated small block, with high-compression pistons is choosy when it comes to octane, too, but the results from normally-aspirated detonation are usually not as "catastrophic" as when it happens with, say, 25 pounds of boost. So, I have to say that the turbo slant six is a problem child in that area. Bear in mind that I originally said a "500-horsepower" turbo slant six. That's what we are talking about, here, But to be realistic, the great bulk of whatever turbocharged slant six motors come to pass, MOST will never see boost levels that high, and the picture changes greatly at 7-10 pounds of boost. But, that wasn't the argument, here. Soooooo...

Advantage, small block

The sound of a well-tuned, high-revving small block at full song, is music to almost everyone's ears. Slant sixes with turbos are quiet: the turbo impeller sort of homoginizes the sound waves...

Advantage small block



Due to the very-limited rpm range (less than 5,500rpm, tops, usually) the slant six turbo motor doesn't need a high rpm ignition system like a high-winding, 500 HP, normally-aspirated small block. A stock distributor will work fine, with no worries about effective spark at 7,000 rpm... 'cause, that boosted slant 6 is never gonna see even 6,000 rpm, much less 7,000...

Advantage, slant six

There are no aftermarket (aluminum, or otherwise) cylinder heads for the slant six, so the best you can do is to port the original head, and add some cheap 1/75"/1.5" valves (some folks have used 318 valves.) And, there's only ONE head to deal with, so there's just no place to spend money (of the quantity the V8 car can absorb) on the head. A complete ported head for a slant 6, ready to run, will be cheaper than a pair of aftermarket V8 heads that will support 500 horsepower, I believe.

Advantage, slant six



I hope that after reading all this meandering post, I have made a case for it being actually cheaper to build a 500 HP turbo slant 6 than it is to make the same amount of power with a normally-aspirated, small block V8.
 
StrokerScamp said:
I thought his point was pretty self explanatory.
Click to expand...

I didn't. It's a not-so-simple situation, regarding torque and horsepower.

For the purposes of our discussions (automobile engines,) horsepower is a number that is arrived at, mathemetically, with torque being one of the factors and rpm the other.

Like the song says, you can't have one without the other...

Torque is twisting force. Horsepower numbers are arrived at by crunching the numbers related to the RATE (RPM) of the torque being produced.

How this plays out is this:

Let's say you have 500 foot pounds of torque at 6,000 rpm. If you reduce the amount of rpm to 3,000, while maintaing the same amount of torque, your horsepower will be cut in half. The same thing is true if you maintain 6,000 rpm and reduce the available torque to 250 foot pounds; your horsepower will be cut in half.

One horsepower is the ability to raise 42,000 pounds one foot, vertically, in one minute. Or, 21,000 pounds, the same distance vertically, in 30 seconds... and on and on.

TIME figures into the horsepower equation as rate of work done.

Torque has no such parameters; twisting force is twisting force. Period!

To show an example of how this works, let's say we have two Dusters that weigh 3,000 pounds each.

One has a 440.

The other has a 340.

The 440 is a mild build with a short-duration cam, 9:1 compression and a 600cfm 4bbl Holley on a 180-degree manifold.

It makes 400 horsepower at 5,000 rpm, horsepower and 500 foot pounds of torque.

The 340 is a more aggressive build, with a fairly long-duration cam, 11:1 pistons and an 750 Holley on a single-plane manifold.

It also makes 400 horsepower, but only 360 foot pounds of torque.

Put them both in the Dusters with optimum gearing and tires and they'll run the same e.t.

They each have 400 horsepower available to move the weight through the quarter-mile. Same weight, same horsepower = same e.t.

BUT, they have wildly varying amounts of torque. Five hundred foot pounds vs. 360.

Doesn't matter; the amount of HORSEPOWER available to move the same amount of weight in the same amount of time, is the same... so, the results will be the same IF they both have setups that take full advantage of their different "personalities."

Lots of gear (5.86:1 and a high rpm stall torque converter for the 340) and not-so-stiff gearing (4.10:1?) for the 440, with a MUCH tighter converter.

So, what wins races?

Horsepower. Same horsepower here = a dead heat.

Lots of torque at high rpm = lots of horsepower.
Lots of horsepower = low e.t.'s.

I'm a mathematical dunce, but even ~I~ can understand that.

A fact that I find interesting, but one that has to do with the way horsepower is determined is, the horsepower and torque numbers will ALWAYS be the same at 5,250 rpm. Always.

Go figure...
 
You'll hear the name "Clifford" come up, but be very careful before you decide to spend any money with Clifford. They have a long and ugly reputation for being a bunch of clowns; see for example here, here, here, here, and here. Much of what they sell is inaccurately described, and a lot of it is not even slightly cost-effective. The good news is that you don't need to go to Clifford to get hot rod parts for slant-6s; there are lots of other, better options. See for example Dutra Duals and header options discussed in this thread and this one, Erson custom cams, HEI ignition upgrade, Mike Jeffreys windage trays, Hurricane intakes, other exotic intakes. Hi-perf engine buildup here, high-perf parts and build info here.
 
Bill Dedman said:
I hope that after reading all this meandering post, I have made a case for it being actually cheaper to build a 500 HP turbo slant 6 than it is to make the same amount of power with a normally-aspirated, small block V8.
Click to expand...

That's a great post Bill. Thanks for taking the time to write and put it out there.
 
fzmax said:
That's a great post Bill. Thanks for taking the time to write and put it out there.
Click to expand...

It's a great post if it doesn't put you to sleep... LOL!!!

Thanks for the kind words!

I think it's mostly true... but, I make mistakes... I just hope they don't cost anybody anything.

Love your avatar... :)
 
A true performance focused enthusiast will have to determine what power level they are after. A 500 HP slant isn't doing it without help, Ie. a turbo or a good shot of nitrous. A 500 HP V-8 will require some serious mods, but is less likely to require "help".

What most people consider a performance Slant is well under 500 HP. 300 is a lot harder to get than most Slanters are willing to accept. Just bolting a header and 4 bbl on a stock Slant won't get you there. Bolting a set of headers and 4 bbl on a 440 will get you much farther. It's just cubic inches. You build a Slant because you want to, not for ultimate performance. Anything done to a Slant will garner bigger numbers when applied to a bigger engine. Physics suck, but there it is. I have done 2 "performance" Slants, and don't regret either, but I know their limitations. I would love to do a Turbo slant someday.

A quick example: I put a bone stock, 60,000 mile '65 383 2 bbl engine in a '72 Valiant 4 door. I added a stock intake, and a 600 cfm 4 bbl. carb with no tuning. 2" soda straw exhaust off the tiny log manifolds. Factory single point ignition, with no tuning. Stock trans with 120,000+ miles. 2.76 rear gears. Car weighed over 3,400 pounds with me in it. It ran in the 14's at over 95 Mph. using only 1st and second gear, and I drove it daily for 4 years. How many mods would it take to do that with a Slant? Plenty. I paid $100 for that 383, and still have it.

Build a slant to be different, and to be cool. Expect to spend some extra dollars if you want to go fast.
 
BBBCUDA said:
A true performance focused enthusiast will have to determine what power level they are after. A 500 HP slant isn't doing it without help, Ie. a turbo or a good shot of nitrous. A 500 HP V-8 will require some serious mods, but is less likely to require "help".

What most people consider a performance Slant is well under 500 HP. 300 is a lot harder to get than most Slanters are willing to accept. Just bolting a header and 4 bbl on a stock Slant won't get you there. Bolting a set of headers and 4 bbl on a 440 will get you much farther. It's just cubic inches. You build a Slant because you want to, not for ultimate performance. Anything done to a Slant will garner bigger numbers when applied to a bigger engine. Physics suck, but there it is. I have done 2 "performance" Slants, and don't regret either, but I know their limitations. I would love to do a Turbo slant someday.

A quick example: I put a bone stock, 60,000 mile '65 383 2 bbl engine in a '72 Valiant 4 door. I added a stock intake, and a 600 cfm 4 bbl. carb with no tuning. 2" soda straw exhaust off the tiny log manifolds. Factory single point ignition, with no tuning. Stock trans with 120,000+ miles. 2.76 rear gears. Car weighed over 3,400 pounds with me in it. It ran in the 14's at over 95 Mph. using only 1st and second gear, and I drove it daily for 4 years. How many mods would it take to do that with a Slant? Plenty. I paid $100 for that 383, and still have it.

Build a slant to be different, and to be cool. Expect to spend some extra dollars if you want to go fast.
Click to expand...


Everything you say is true... I have no problem with any of it...

But, boost is addictive... LOL

So, consider this: [ame="http://www.youtube.com/watch?v=pPe_vHwZsF4"]Slant Six Turbo 1970 Dodge Dart 1/4 Mile pass - YouTube[/ame]

Tom Wolfe's stock, 100,000-mile 225 slant six with a junkyard Buick turbo on it....

He added a 2bbl carb and nothing else... stock everything, and went 12.95 and 104...

Now, with some better parts, the same car runs 11-flat @ 120.... into a 15-mph headwind.

[ame="http://www.youtube.com/watch?v=EAxRmoDgsdY"]Turbo charged Slant 6 11.02 @ 120.56 - YouTube[/ame]

Just a viable alternative to a 340/360, I think.
 
Bill, believe me, I've watched those videos many times. I really want to do a turbo Slant. Boost works on bigger engines too though... I kept my last slant with the 4 bbl. header, ported head and .530" solid.
 
BBBCUDA said:
Bill, believe me, I've watched those videos many times. I really want to do a turbo Slant. Boost works on bigger engines too though... I kept my last slant with the 4 bbl. header, ported head and .530" solid.
Click to expand...

Oh, you are SOOO right!

If you want to go REAL fast, turbo a big block!!!:blob:

I think, for sane people, though a 500 horsepower street car is pretty much the limit for safe, sane driving. My Vortech-supercharged 360 Magnum makes around 500 HP and in a 3,330-pound '72 Valiant goes about as fast and as quick as I want to go on the street.

Will it take a Hayabusa from a traffic light? No... but it will scare him... LOL!

I'm 73 years old and I guess I just am losing it, but that Valiant scares me... It goes fast enough, quick enough, to get me into trouble in a heartbeat.

The slant six car we are building will (if it runs at all, like it should be capable of,) make MY Valiant look like it's backing up... seeing as how it's got about the same amount of power, in a 500-pound lighter body...

I don't really want to go any faster than that...

But, there are folks who are looking for 700+ horsepower (or, more), and you probably aren't going to find that with a slant six... turbo, nitrous, or both.

To them, I say, have it it!! Twin turbos on a 510-inch 383 stroker in a Duster could be lots of fun... if I weren't such a wimp!

But, 500 is going to be plenty for me, I think.:cheers:

Now, the next problem is finding it (that 500 HP); I may get this monstrosity bolted together and find I have built a 14-second car... that is always possible!


TALK IS CHEAP; WE'LL SEE!!! :prayer:
 
This thread is going in the file for future reference. I would be happy with a slant that had anything close to 300 horses. I'm not out to race, but to have a great looking car with respectable performance. I had never heard of other companies that build performance parts for slants besides Clifford and Offenhauser.

The only reason that this has intriqued me, is that so many A bodies came with slants in them and they also look great detailed and dressed up. Dusters and Darts are beautiful cars, very sporty looking. I got really excited when I saw the videos that Bill posted below and all the others on youtube that deal with performance slant 6s. They Hyper pak is also very interesting.
 
I doubt my last Slant made any where near 300 HP, in fact I would guarantee it. The light weight helped, and so did the 4.86 gears. It surprised many people on the street.
 
BBBCUDA said:
I doubt my last Slant made any where near 300 HP, in fact I would guarantee it. The light weight helped, and so did the 4.86 gears. It surprised many people on the street.
Click to expand...

There's an online calculator at:

http://www.wallaceracing.com/et-hp-mph.php

It is not 100-percent accurate, by any means, but is fun to use and I think, comes fairly close to figuring out flywheel horsepower if you give it the weight, e.t. and mph. I believe it's useful as a tool for figuring out how much adding weight, or subtracting it from a given combination will help or hurt performance.

For example, it says that a 3,300-pound car needs 300 horsepower to run a 12.95 @ 103 mph. I find it interesting that those numbers are almost the exact ones that were turned by Tom Wolfe's Dart turned with the addition of just a 2bbl carb and a junkyard turbo.

The program , when fed the same HP number, but the weight was cut 500 pounds to 2.800, reported an increase in mph to 109 and it dropped the e.t. from 12.95 to 12.26-seconds. No other changes.


Like I said, those numbers are not exact, but they probably represent a good "ballpark" guess.

A 300 HP, normally-aspirated, slant six would be a HOSS!!!:cheers:

That's 1.33 horsepower-per-cubic-inch.

Guzzi Mark Ethridge's Valiant runs 11.50 @ 2,350-pounds; and that's 305 HP according to this online calculator.

Mark's car is a rocket, and has pretty much, a full-race engine, I think.

It would take something pretty special to beat his performance on gas/no power-adder.
 
Sounds a lot like V8 mods? Yes, what I was saying is that after spending all of that money on a slant, it still carries not much residual value, other than selling off some bolt-ons.
Building up a smallblock, it is still worth something and a heck of a lot easier to sell(in the car or not) if need be. If a /6 build is what you want to do,that's just fine, but if you change your mind and want small block after all, be prepared to take a bigger hit $$$ wise.
 
Elwood67 said:
Sounds a lot like V8 mods? Yes, what I was saying is that after spending all of that money on a slant, it still carries not much residual value, other than selling off some bolt-ons.
Building up a smallblock, it is still worth something and a heck of a lot easier to sell(in the car or not) if need be. If a /6 build is what you want to do,that's just fine, but if you change your mind and want small block after all, be prepared to take a bigger hit $$$ wise.
Click to expand...

That's all true, I think.

But, I've never built a car with the idea of selling it. I can't think that far ahead!!!

That's probably why I've never had any money...

Oh well...
 
Bill Dedman said:
I didn't. It's a not-so-simple situation, regarding torque and horsepower.

For the purposes of our discussions (automobile engines,) horsepower is a number that is arrived at, mathemetically, with torque being one of the factors and rpm the other.

Like the song says, you can't have one without the other...

Torque is twisting force. Horsepower numbers are arrived at by crunching the numbers related to the RATE (RPM) of the torque being produced.

How this plays out is this:

Let's say you have 500 foot pounds of torque at 6,000 rpm. If you reduce the amount of rpm to 3,000, while maintaing the same amount of torque, your horsepower will be cut in half. The same thing is true if you maintain 6,000 rpm and reduce the available torque to 250 foot pounds; your horsepower will be cut in half.

One horsepower is the ability to raise 42,000 pounds one foot, vertically, in one minute. Or, 21,000 pounds, the same distance vertically, in 30 seconds... and on and on.

TIME figures into the horsepower equation as rate of work done.

Torque has no such parameters; twisting force is twisting force. Period!

To show an example of how this works, let's say we have two Dusters that weigh 3,000 pounds each.

One has a 440.

The other has a 340.

The 440 is a mild build with a short-duration cam, 9:1 compression and a 600cfm 4bbl Holley on a 180-degree manifold.

It makes 400 horsepower at 5,000 rpm, horsepower and 500 foot pounds of torque.

The 340 is a more aggressive build, with a fairly long-duration cam, 11:1 pistons and an 750 Holley on a single-plane manifold.

It also makes 400 horsepower, but only 360 foot pounds of torque.

Put them both in the Dusters with optimum gearing and tires and they'll run the same e.t.

They each have 400 horsepower available to move the weight through the quarter-mile. Same weight, same horsepower = same e.t.

BUT, they have wildly varying amounts of torque. Five hundred foot pounds vs. 360.

Doesn't matter; the amount of HORSEPOWER available to move the same amount of weight in the same amount of time, is the same... so, the results will be the same IF they both have setups that take full advantage of their different "personalities."

Lots of gear (5.86:1 and a high rpm stall torque converter for the 340) and not-so-stiff gearing (4.10:1?) for the 440, with a MUCH tighter converter.

So, what wins races?

Horsepower. Same horsepower here = a dead heat.

Lots of torque at high rpm = lots of horsepower.
Lots of horsepower = low e.t.'s.

I'm a mathematical dunce, but even ~I~ can understand that.

A fact that I find interesting, but one that has to do with the way horsepower is determined is, the horsepower and torque numbers will ALWAYS be the same at 5,250 rpm. Always.

Go figure...
Click to expand...

But no mathematics will tell you about gearing it correctly, as every engine is different nomatter if they are the same.
Usually, torque wins the day at a race track, and the ability to get it to bite the ground and go....hence, special shockies, spring rates, tyres, etc.
I had a mild slant 6 that handled like a train on rails, but was hopeless at a good 1/4 mile time.....16 secs @ 86mph.....4 sp manual ( 1st gear ratio was 2.82:1), 3.23 gears, street tyres, and very stiff suspension......but up against mild 302/351C V8's, 253/308H V8's, it would eat them.....and it did a true 120 mph @ 5,000 rpm.....and it had bags of torque.
I never did a measure of the CR ( cc the head and such), but on a dry compression test, it had 240 psi ( had to use a screw in tester as the push in one wouldn't seal) on all 6 cyl's.....so it's a guess.
Anyway, i'm in the process of building another slant six....will see how that goes.
 
You did not do 120mph at 5000rpm in a1/4.My car has done 124mph over 6,000 rpm with a 10.70 time slip running 3.90 gears,60 shot.I have time slips.Guzzi Mark
 
madmax/6 said:
You did not do 120mph at 5000rpm in a1/4.My car has done 124mph over 6,000 rpm with a 10.70 time slip running 3.90 gears,60 shot.I have time slips.Guzzi Mark
Click to expand...

Mark,

I think he's talking about top speed, not quarter-mile performance.

Your car is AMAZING, to run the fast and quick with just a 60-shot!

What a rocket...:cheers:
 
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