What would you do? Slant performance

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porterracing

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Hey everybody I have been saving a little cash and think its time for some more POWER! I have a stock 225 slant 6 and before everybody starts on the V8 ban wagon, go ahead and hope off as this is not the right ride for you. I understand a V8 will give more power than I could get from a slant but I like the slant and don't have the required cash for that purchase... Okay back on track, I would like to get your guys ideas on a $2,000 budget. Cam what dimensions would be good, head work, intake, exhaust... It seems every time read a comment there are never specs given and there is always a comment or two that contradict the last...
I was originally looking at the dual 38 weber intake and dual exhaust from clifford, but after many saying bad things about clifford and having no experience with weber carbs I decided against it...
Basically what would you do to a slant 6 with a $2,000 budget to make the most power and torque. This is my first mopar build and am pretty lost on whats best so all the help is much appreciated! Thanks-Zach
:burnout:
 
I always figure you should start with gears and exhaust.
That way you'll make the most of every engine mod.
But with a /6 the head is the weakest link in flow and compression. I'd make a trip to a scrapyard and pick a couple of heads and practice porting on one of them will saving the other for the final with milling and porting.

So I'd start with as much gear as your willing to live with.
 
Think about this;
-With bolt-ons/ins and $2000, what can you achieve? Say 15%? Say 20%....So how does that translate to your ride? Well, If you start with 140 hp, then add 20%, you get 168hp.
If you are working on a 3000 plus car, you have increased the performance from 21.4 pounds per hp, to 17.9.Now consider; that the extra hp comes at the top of the rev range; 54mph at 4500rpm,at the top of first gear with 2.73s
-But suppose you found 40hp;with a cam-kit,headers, a 4bbl, and a bump in compression.Cuz that's all you have to work with,right? So now you are up to 180hp, and you are down to 16.7pounds per hp. And now you have given up low rpm performance, cuz that's how it works.
-There is just 3 ways to make more power; rpm, cid, or supercharging. And if you choose rpm; you always trade away low rpm for high rpm

So my recommendation is gears and a tune up.And maybe an exhaust,Just as 273 said.
 
Thinking about this guys build... .01 mill head shave, oversized stainless valves, .60 overbore, comp cam kit, hardened seats, head port, duel exhaust, offenhauser intake, 600 cfm carb, 355 gear...
 
Although the head is easiest to mill, I'd consider decking the block 80-90 thou or so after measuring how far down in the hole the pistons are. Then do the head mill to get your compression where you want it to be - measurements, measurement, measurements!
 
porterracing said:
Thinking about this guys build... .01 mill head shave, oversized stainless valves, .60 overbore, comp cam kit, hardened seats, head port, duel exhaust, offenhauser intake, 600 cfm carb, 355 gear...
Click to expand...

A full build and gears I'd think you'd need more than $2000.

Why go with harden seats just start with newer head.

I'd do it in 3 stages gears, intake and exhaust even though at this point it's just eye candy but sets up the next stage head and cam.

But if your /6 needs rebuilding I'd look for a low mile one or up your budget.

Carb a little big the rule of thumb is 2 cfms per hp.
I wouldn't go larger than 500 cfms 390 probably better.
 
AJ/FormS said:
Think about this;
-With bolt-ons/ins and $2000, what can you achieve? Say 15%? Say 20%....So how does that translate to your ride? Well, If you start with 140 hp, then add 20%, you get 168hp.
If you are working on a 3000 plus car, you have increased the performance from 21.4 pounds per hp, to 17.9.Now consider; that the extra hp comes at the top of the rev range; 54mph at 4500rpm,at the top of first gear with 2.73s
-But suppose you found 40hp;with a cam-kit,headers, a 4bbl, and a bump in compression.Cuz that's all you have to work with,right? So now you are up to 180hp, and you are down to 16.7pounds per hp. And now you have given up low rpm performance, cuz that's how it works.
-There is just 3 ways to make more power; rpm, cid, or supercharging. And if you choose rpm; you always trade away low rpm for high rpm

So my recommendation is gears and a tune up.And maybe an exhaust,Just as 273 said.
Click to expand...

I agree but there's a little area on a low performance engine were you can extend the powerband without
overly effecting the off idle power. The trick is saying when on cam, carb heads etc...probably can up the peak from 3500 ish to 4500-5000 without giving up much down low. Still were talking sub 200 hp engine.
 
The 3.55:1 rear gear is pretty much the standard street gear not saying that you have to go more but it's a compromised gear for an average V8 nevermind /6
Just to put gears prospective say you have /6 vs 273 vs 318 vs 440 each with 200 hp cause gears don't make up for hp only torque. So say your gonna compare how much gear your /6 needs compared to 3.23:1 geared 273/318/440 would be 3.91/4.56/6.32 respectively with the /6. I'd try to step up at least one or two gear steps especially if you don't do a lot of highway driving.
 
373, 391, or 410? 60 mph is the max I take her and its usually only for 8 to 10 miles ... just want to get there quicker! Really this is the first car I've ever had that cant do a burn out... lol
 
AJ/FormS said:
-There is just 3 ways to make more power; rpm, cid, or supercharging. And if you choose rpm; you always trade away low rpm for high rpm
Click to expand...
100% incorrect,increasing efficiency makes more power.Whether it is mass air,
combustion,fuel distribution/mixture/quality,timing optimization,or intake/exh. tract
tuning. ANY increase in torque is an increase in power automatically,regardless of the
RPM it is increased at,and ANY increase in efficiency is an increase in torque regardless
of the RPM just the same.
There's an old rule of thumb that is almost true every time,there is nearly a full
second of ET left on a new engine package after it's 1st solid pass,with no eng. com-
ponent changes at all. I've seen that prove out many times.Sometimes you get the
lucky "hit",and the car runs like a raped ape out of the gate, and there is only a couple
tenths left in it.But that's not the rule.
As much compression the fuel your using will allow,is a win top to bottom.
The 225 is only second worst to the 2.5L for valve size/displacement deficiency
Porting a stock valved head is a good way to piss away your time for nothing.
Use carburetion just a little more than you need and DIAL IT IN !!
A better cam is a must, but you can't go far B4 you'll need a torque converter.
A tuned and unrestricted exh. is self explanatory,conservative primaries.
Giving you actual numbers/specs/recommendations would require knowing what you
are willing and capable of doing, and putting up with driveability wise.This ?? has been
done to death in this forum,search & read for a Sunday here,plenty of coverage.
 
porterracing said:
373, 391, or 410? 60 mph is the max I take her and its usually only for 8 to 10 miles ... just want to get there quicker! Really this is the first car I've ever had that cant do a burn out... lol
Click to expand...


If you don't care 4.10's all the way it would only rev about 3200 rpm at 60 mph
 
Killer6 said:
100% incorrect,increasing efficiency makes more power.Whether it is mass air,
combustion,fuel distribution/mixture/quality,timing optimization,or intake/exh. tract
tuning. ANY increase in torque is an increase in power automatically,regardless of the
RPM it is increased at,and ANY increase in efficiency is an increase in torque regardless
of the RPM just the same.
There's an old rule of thumb that is almost true every time,there is nearly a full
second of ET left on a new engine package after it's 1st solid pass,with no eng. com-
ponent changes at all. I've seen that prove out many times.Sometimes you get the
lucky "hit",and the car runs like a raped ape out of the gate, and there is only a couple
tenths left in it.But that's not the rule.
As much compression the fuel your using will allow,is a win top to bottom.
The 225 is only second worst to the 2.5L for valve size/displacement deficiency
Porting a stock valved head is a good way to piss away your time for nothing.
Use carburetion just a little more than you need and DIAL IT IN !!
A better cam is a must, but you can't go far B4 you'll need a torque converter.
A tuned and unrestricted exh. is self explanatory,conservative primaries.
Giving you actual numbers/specs/recommendations would require knowing what you
are willing and capable of doing, and putting up with driveability wise.This ?? has been
done to death in this forum,search & read for a Sunday here,plenty of coverage.
Click to expand...


Semantics and details. Mr newbe knows nothing about such.

And my experience with slantys is that camming it up makes the bottom soft; and not just comparatively either, but absolutely.So after spending a bunch of money all I got was a slanty with passing power, that couldn't fight it's way out of a wet paper bag.Sure, I got it to work with gears and a Hi-stall. But honestly, IMO, Spending all that coin was not worth it, And I will never do it again.For a quarter as much money I coulda had twice the torque and power, and kept my hiway gears.
 
AJ/FormS said:
Semantics and details. Mr newbe knows nothing about such.

And my experience with slantys is that camming it up makes the bottom soft; and not just comparatively either, but absolutely.So after spending a bunch of money all I got was a slanty with passing power, that couldn't fight it's way out of a wet paper bag.Sure, I got it to work with gears and a Hi-stall. But honestly, IMO, Spending all that coin was not worth it, And I will never do it again.For a quarter as much money I coulda had twice the torque and power, and kept my hiway gears.
Click to expand...

Well, we all have to go through life and find things out the hard way lol.... As long as you stay safe and nobody's gets harmed go ahead and take the time, effort, and money to ascertain what your goals are for this project. You most likely won't be happy with the end result but it's your car....

I personally would not touch this project. Go on Clist and find a complete V8 A body with a good operating Drivetrain. They are out there and you will be light years ahead of this current program. That is reality and the comments come from a guy who has been down the 6 Cylinder road in the past....

Good luck,
JW
 
like he said, lots of info and arguments on this subject here. search and read. also, go over to slantsix.org. and again read all the info there.

these are correct about logic and the small block for sure.

wouldn't life be great IF we could find a guy closeby and drive his SLANT and have his receipe he followed on his build!???? and see if it gives the power desired!!????????
 
I dunno man. I've had bunches of slants, even currently have a great running 170 in my dd '64 dart, but I've never been able to pull the trigger on building one. It just costs to damn much to actually do one right. I started collecting parts one time. Had a HyperPak intake, Holley 390, and a pair if Clifford headers. All of which I bought used, an with just those parts I had $800! I did the math, and by the time I had everything needed, including headwork and machining, I'd have near $3500 in just the motor! It just doesn't make sense.

I ended up selling the hotrod parts and used the money to buy a Pertronix for the dizzy, added a 2.25" exhaust, and swapped in a 8.25" with a 3.55fd and a SureGrip. And I'm currently building a 360 to replace the slant eventually.
 
AJ/FormS said:
Semantics and details. Mr newbe knows nothing about such.

IMO, Spending all that coin was not worth it, And I will never do it again.
Click to expand...

Amen brother.....I will never do it again either.

Clifford intake/headers
Eddie 500
Erson Cam
Big valve head shaved, ported.
Elec ignition
3.55
Alllll the buuulshit.
It shoots around ok, but my stock 318 car, with a 4bbl and exhaust will walk all over it. :wack:

Now im talking with my partner about putting a turbo into the thing. Trying not to get sucked into the Vortex, litterally. Especially when I have a hot little 340 complete on a stand. :banghead:

My suggestion, go Small Block. Or you can go over to .org. Sounds like youve been there already. Spend your 2 grand, and get waxxed by a Camry.

Sorry buddy, sure this isnt what you want to hear. But ive been there, done that.
 
do a .030 boer with a decent cam and a 500 edelbrock with dual hooker headers and a little head work.
 

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AJ/FormS said:
Semantics and details. Mr newbe knows nothing about such.

And my experience with slantys is that camming it up makes the bottom soft; But honestly, IMO, Spending all that coin was not worth it, And I will never do it again.For a quarter as much money I coulda had twice the torque and power, and kept my hiway gears.
Click to expand...

I'm not privvy to what "Mr. newbie" does or doesn't know, but he did ask for
suggestions on how to improve his /6 output, that is what I'm offering. As I was pointing
out, the 3 methods you listed are not the ONLY way to improve output.When I built mine
28yrs. ago, I did it to challenge and teach myself, and it was worth every penny. At no
point did I delude myself that it would keep up w/my smallblock dart, but I beat plenty of
V-8's w/that car, and it was a source of pride to do so.
The OP said he didn't want to V-8 swap, I think he may believe that is more
costly than it is, certainly a scrapyard bound donor car would get it done for half the
total $ invested. I would never take back the SB swap I did to my 1st dart either,that
car also got a four gear and 8.75,and it donated the slanty I built for the other.
 
the hard part of some many engine builds 1. is having a blueprint and 2. a known hp and torque that you will get from it, and 3. the total associated costs of that build???? and THEN understanding what kind of seat of the pants performance you will get from that build and 4. with the other variables you have, T C, rear gears, carbtires, exhaust, etc ?????
 
To build a /6 has to be a labour of love not money sense.
The reason people recommend 360 all the time cause it just makes $$$$ sense. A good running 360/Magnum with 4bbl cam and exhaust could be had for the $2000. Problem with /6 is the head there just not a lot of potential hp in there with cam header and intake your lucky you to get stock 318 2bbl hp with 2/3 the torque.
273/318 are a cam headers and carb away from 300 hp and 340/360 are that away from 400 hp.
 
The most power to be gained from a /6 is going to come from more compression. I don't know what machine shop work goes for in you neck of the woods. Plan on a rebuild kit, milling the block and head to .090-.100 combined, a camshaft, and oversized valves. Depending on the condition of the block, it ay be necessary to bore out the cylinders. Save $s; if not needed, don't do it. There's not that much more power to be gained from boring a /6 out, IMO. For seat of the pants feel, try to find a 3.23:1 rear end. Your $2k might just cover it.

Obviously, more intake and exhaust capacity will help, but bang for the buck do the internals first. The rest is lawn furniture you can add as time and money allow. I don't recommend more than a 3.23:1 because the 225 is not a high winder. You could get better feel from a 3.55:1, but it would probably crater your fuel mileage.

Remember in being seduced by a V-8, the bell housings are different due to starter location. A new, for you at least, A/T would be needed, too. It's funny how folks say a V-8 is possible for $2K, until it is time to lay out the cash. All of a sudden there's a great divide between what someone says it can be bought for and what the going rates for the stuff is. Don't believe me? See the For Sale forums here on FABO.
 
1st question, what are we starting with, year and car?

I would not get too exotic. Mill the head about .080, get a good valve job, get a cam in the 250 to 260 duration range, matching valve springs or 340 valve springs, OEM Super Six intake carb and throttle linkage and kickdown linkage, Double roller timing chain, electronic distributor, Chrome ECU, custom exhaust single 2 1/4 pipe and straight through or other high flow muffler. You will now have good power and better mpg.
 
4.10's won't turn it into a revver you'll hit 4500 rpm at 35 mph in 1st, 60 mph in 2nd and 85 mph in 3rd. And 3200 rpm at 60 mph in 3rd. A good compromise would and 80's tranny with the deeper 2.74 1st and 1.54 2nd with 3.55:1 would almost be like 4.10's in 1st and 3.91's in 2nd with 3.55 cruising in 3rd. Overall a little slower but very similar in 1st and 2nd. This tranny is probably a best swap for all slants out there.
 
2 Darts said:
Remember in being seduced by a V-8, the bell housings are different due to starter location. A new, for you at least, A/T would be needed, too. It's funny how folks say a V-8 is possible for $2K, until it is time to lay out the cash. All of a sudden there's a great divide between what someone says it can be bought for and what the going rates for the stuff is. Don't believe me? See the For Sale forums here on FABO.
Click to expand...

You can't find a 318/auto junkyard dog for under$1000?????,forget the
headers,just add duals. Used alum. intake & carb combos from guys stepping up to
something bigger/better for under $350? Cams readily available for less than any slanty
grind? For just those parts alone on an un-rebuilt sound running 318 you have a low 14
second ride,you will be lucky to spend twice that to get your slant to run that...IF...that
is, you get it to run that. And a 360 is no harder to install,and not that much more coin,
and you're in the 13's, based on strictly$$$ it's no contest.
 
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