RustyRatRod's Guide To Hot Rod Bliss

[DentalDart]

I dont like RRR's guide... it makes me think I shouldn't spend money.... every time I get to the point of "it doesn't need anything else..." I want more power... lol.

Honestly this is a really good guide. Get the car running and enjoy it... or be like me... get it running then immediately take it apart to do something on it that wasn't "needed..." oops...

 

[Norm.P]

This was a thoughtful, well reasoned and logical way to build out a vehicle. Thank you for this post.

 

[Cruisingram]

I agree with 99.999% of what you say- except I do have an interesting experience with exhaust testing regarding the 2.5" exhaust and stuff. Now- I don't have much expereince with /6s, and this is my first build on one in fact. I was around a speed shop, my uncles, in the early 80s and we did a ton of exhaust testing on SB from stock to crazy, and same with BB. Even with stock exhaust manifolds, we increased HP and torque with bigger exhaust pipes, and even ran straight stock exhaust manifolds open with no pipe. We had to ad short "stubbies" on them, but even with, I think it was about 2' if I recall, straight pipe exhaust off the stock exhaust manifolds, we developed torque earlier and better peak HP across the board.

 

[derrinober]

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[skep419]

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Just a friendly heads up there is a Bookmark tab at the bottom left side of the page.

 

[Norm.P]

This is the best, most logical and practical write up I have ever read. Thanks!

RustyRatRod's Guide To Hot Rod Bliss

Recent threads have prompted me to write this up.
It seems people get caught up in marketing and hype that advertisers spread through ads in magazines and on the internet and through internet forums such as this. Although some of these marketing tactics are legitimate, I want to dispel a few myths.

1). You do not need a large by huge MSD or any other fancy brand ignition system on most vehicles. All out race cars racing for money and points need the hot spark and consistency these type systems can deliver. Your everyday or even weekend race car does not.
Stock ignition systems are perfectly suitable for everyday street applications. That's what they were designed for. They can be upgraded to even withstand the rigors or an all out race car, if you so desire.

2). When choosing a camshaft, always err on the smaller side of any multiple choice decision. Why? Because of all of the outside influences from the aftermarket through magazine ads and the internet that seem to indicate that bigger is better. It's not.
You will be much happier with a camshaft that's too small than one that is too large. We all get caught up in what an engine will sound like. Throw that out the window. If an engine is built to true HP standards, it will have the snappy sound of an HP engine, regardless of camshaft choice. The higher cylinder pressure, free flowing intake and exhaust will all have a direct impact on how an engine sounds.

Stock factory camshafts were designed for everyday driving, within RPM ranges of idle to about 4500 or so RPM. Guess what? That's right were 90% or more of street driving is done, regardless of what type vehicle you have. That means with a few upgrades such as intake and exhaust and carburetor, an engine with a stock camshaft will respond surprisingly well!

Factory HP camshafts were a fantastic marvel. Although considered "small" or "baby" by some, consider this. The factory had to design them so as to still retain some form of mileage, street manners and ability to run power accessories with a good vacuum signal, all the while exceeding the performance of the stock camshaft. That's a pretty tall order.
Most people don't realize a stock HP camshaft will pull well beyond 5K RPM. Ask yourself honestly. How often and how long will your engine be operated in that RPM range? Chances are your honest answer is "not very often".

The truth of it is, the factory HP packages are hard to improve upon. Sure, you can build an engine that easily eclipses them, but at what cost? The inability to run power brakes? A poor idle? Poor drivability? Extremely poor bottom end performance? Poor mileage?
I have seen stone stock 340 Darts get close to 20 MPG and then spank some high 13 second quarter mile times with slicks. That's a ball of badassary that's tough to duplicate. And the recipe is already laid out.

No cooling problems. No stupid oil pressure problems. No dumbass header leaks. It's all right there in front of you.

Aftermarket camshafts are always ground with advance figured in. Usually 4* is the industry standard, but it can vary. Know why? Because 90% or more of people out there make two mistakes.

First, they choose a camshaft that's too "large" for their application. Second, they don't degree the camshaft. Make these two mistakes together, and you will have an engine that might sound good, but it won't pull a greasy string out of a cat's ***.

This is why you err on the small side. Have a stock 318 and want to re cam? Then it's probably best not to go over 220 degrees @ .050" lift. Considering that stock camshafts have a good bit less then 200* @ .050", going over .200 is an upgrade.

How many times have you seen or heard someone that revved a totally stock engine above 5K RPM? A LOT. So, what makes you think you need 240* @ .050" to make one run strong? You do not. That will be wasted duration on most any street engine.

Some stock camshafts were in the 190* range @ .050". So, a 220* @ .050" is a huge upgrade. With everything matching the cam, intake, carb and exhaust, there's no reason that engine cannot pull past 6K RPM. There is NO need for some thing bigger other than sound and bragging rights. And if it won't run worth a darn, what's the sound worth?

3). Same considerations should be taken with the drive train. Why does a street car need a 3K RPM stall converter? Kinda makes it not a street car anymore. Why does a mild street engine need all that? In most instances, you can get by with nothing more than the stock Hi Stall 340 converter......although I will admit converter technology has exploded in the past 20 years.

A good converter that can flash to your matched combination's stall speed, yet still remain "tight" while cruising, is a big bonus. The converter is probably the single biggest consideration to make in a hot rod. No skimping here can do you any good. Get a GOOD converter.

4). Why do you need an 850 double pumper on the street? Because Chevy Action said so? Wrong. Most of these online carburetor formulas are right on the mark. Around 360 cubes needs something like 600-650 CFM to be happy. Find a calculator and use it.

5). Do you need 2.5" primary tube headers on a street car? Yeah, if you want bottom end to SUCK, you might. Stick with the 1 5/8 tube and you will be fine. As to brand, I ain't goin there. But lets just say if I ever build another A body, it will sit at the stock ride height, not some ghetto lookin stuff scrapin the ground, so Summit headers will work for ME.

6). With all this mildness going on, why in the world would you need a 4.10 gear out back? Unless you are running an overdrive, you don't. I have seen FIRST HAND in my life time a stone stock 340 Duster mop the FLOOR with an LS6 454 Chevelle. It was pretty embarrassing.

Why stray too far from such a FANTASTIC formula? We all see it on here everyday. People asking "What's the best......."

The best gear is usually what matches what you will be DOING with the car. Not what you WANT. Not what some Chevy guy told you. Not what you read on some forum or in some magazine.

Somewhere between 3:1 and 4:1 works best. If you are using an overdrive transmission, closer to 4:1 is better. If not, probably 3:23 or 3:55.

Use your head. Ask around. Don't fall for gimmicks. Don't try to build a race car to drive back and forth to work everyday. The farther you get from the factory HP packages, the more "unstreetable" it will be.

Pretty simple, really.


Thank you drive through.

 

[Cruisingram]

I would like to also add what costs money and gives the most bang for the buck

Overall thing I have learned from doing over 100 cars in my lifetime

1) Write down a plan with what you want to do to the car, what you want it to do with it when you are done, and try not to wander!

2) restore it as you take it off, don't tear it all down at once and restore it, if you can. Body work and rust repair is the hardest and costliest- start with it first. Get it looking good first is my motto, then each piece that comes off, gets restored, THEN stored. So when I go to say, put back on the brakes after the whole car is done, - don't have to go buy brake parts! I take off the alternator, if I plan on replacing it, I buy a new one then. If you can't afford to do it this way, you can't afford the build period.



2) Good suspension delivers the most bang for the buck for performance of any kind- modify the suspension with a plan in mind first, then go for other mods- sky is the limit with HP when you can get that HP to the ground!

3) Transmission is next, THEN engine. However, this can be tricky, as you have to have a basic idea of what your motor will be.

 

[PScamp74]

So, absolutely great stuff, not quite finished with all 1400 pages..lol...but I have a question
Does the motor built for RV applications have a different cam to produce more torque?
And....how well will it perform straight across into my '74 Scamp?? (I know it won't just fall off in there and that there's a lot to do to make it happen), but generally speaking wouldn't it pull the tires off of it just the way it is?
And, I'm doing the same thing in my B body '73 Charger SE... should I go through them and change anything?

 

[PScamp74]

Yes, I did omit clutches, didn't I?

Same theory. Avoid the stupidness of a race bred clutch in a street car. Even if you are gonna blow it out at the strip only a couple of times a year, a good brand NEW clutch kit is the way to go.

When I worked at the transmission shop, we use LUK brand clutches and had great success with them. I knew about them before, but had never used one. I have one in my F250 now and it works fine.

They are made both in the US and Europe. Very high quality and affordable. I also like Zoom (Perfection) products. They too are made in USA and also Asia. I have run the Centerforce stuff before, but had a weight come off and destroy a clutch and bellhousing in a Chevelle I had years ago. I have read where this is a recurring problem these days with Centerforce.

That's good stuff, it's about time for a new one in the trusty 'ol 65 F100 Custom Cab...I was looking at them already and you all just changed my view, I just need a good clutch and I would have wasted $ had I not read this thread. Thanks a bunch y'all.

 

[rumblefish360]

So, absolutely great stuff, not quite finished with all 1400 pages..lol...but I have a question
Does the motor built for RV applications have a different cam to produce more torque?

An “RV motor” or “cam” is just a small cam that is slightly larger than stock in duration and lift to help make more power.

And....how well will it perform straight across into my '74 Scamp?? (I know it won't just fall off in there and that there's a lot to do to make it happen), but generally speaking wouldn't it pull the tires off of it just the way it is?
And, I'm doing the same thing in my B body '73 Charger SE... should I go through them and change anything?

How well will it perform in your car is a Compilation of various items you did not list. We would need a crystal ball (an actual working Chrystal ball that is) to know how it will do in your exact car.

You ask another question that contains what I guess is slang of which I have no idea what your talking about when you said, “but generally speaking wouldn't it pull the tires off of it just the way it is?.”

I don’t know what your asking here. “Pull the tires off of it?”
I don’t know what that means, or what your trying to say or ask.

(Edit, grammer, whoops!)

 

[273]

So, absolutely great stuff, not quite finished with all 1400 pages..lol...but I have a question
Does the motor built for RV applications have a different cam to produce more torque?
And....how well will it perform straight across into my '74 Scamp?? (I know it won't just fall off in there and that there's a lot to do to make it happen), but generally speaking wouldn't it pull the tires off of it just the way it is?
And, I'm doing the same thing in my B body '73 Charger SE... should I go through them and change anything?

So called RV application, it's not really about more torque. Torque is mainly based on displacement most engines will fall in between 1 to 1.45 lbs-ft per Cid, for most average street builds gonna be more like 1.1 - 1.25 lbs-ft per Cid, if your above 1.2 your doing good, the other mainly way is Volumetric efficiency (VE) how well your filling the cylinder in percentage so basically actual displacement being used which cam among other things effect this.

Now for RV basically doesn't mean more torque but where torque is made, for a street car off idle to 3000 rpm is more important 'rv range' than 3000-5500 rpm street performance range. Most low power/truck type engines have a powerband of idle - 4500 rpm. It's hard overly increase power in the idle - 2500/3000 rpm range the trick with a street type performance engine is to increase the useable powerband from 4500 to 5000/5500 rpm without losing much and or small gain down low idle - 2500 rpm, higher stall deeper gears lighter car etc... Makes that less important. Efficiency is the third way, mainly low restriction intake and exhaust 'pumping loss' Cr there's others but those are the main. So it's about what's more important idle-3000 or 3000 - 5500 and the balance/compromise of the two.

And more direct to your question cam has the biggest role in this.

 

[rumblefish360]

So called RV application, it's not really about more torque.

Yes it is, it’s all about the torque. The idea of the “RV” cam was help more easily move a heavier vehicle.

Torque is mainly based on displacement most engines will fall in between 1 to 1.45 lbs-ft per Cid, for most average street builds gonna be more like 1.1 - 1.25 lbs-ft per Cid, if your above 1.2 your doing good, the other mainly way is Volumetric efficiency (VE) how well your filling the cylinder in percentage so basically actual displacement being used which cam among other things effect this.

Not exactly correct ether. Never mind the values of torque you place on the displacements. For one it’s to general. Second, it’s misleading. The main focus of the “RV” cam is to increase the amount of air and fuel to make more power for more torque no matter the size of the engine. While a bigger engine “should” make more torque, this is not the actual case since depending on the year, some small blocks out power big blocks. During the dark years of the first introduced emissions standards that cut power dramatically during the era which spans from ‘72 on up for decades, even the big blocks were struggling to pull and push around small campers. Hence the introduction of the RV cam & as suggested by name, to help the RV vehicles.

While volumetric efficiency has a big roll in power production, it’s not the most easily fixed with OEM / stock parts. The OEM parts only work so well so you just increase the amount of time the valve is open to fill up the cylinder a little more.

Now for RV basically doesn't mean more torque but where torque is made,

Mostly very wrong. While the improved torque is the goal, the main idea of the RV cam’s rpm band is a few hundred rpm above the OEM cam which is sometimes as low as 600/700 rpm starting point. The RV cam is a few hundred above this mark, camshaft dependent.

And below you over estimate and push the camshaft as if it was pushing the rpm limits beyond its basic usage of description. This is so not the case.

Being the OE camshaft is very small in most cases never mind the big 114 LSA’s, the RV cam (normally) narrows the LSA, increases the duration a minor amount as well as the lift.

The rpm band of the cam barley increases any meaningful amount.

for a street car off idle to 3000 rpm is more important 'rv range' than 3000-5500 rpm street performance range. Most low power/truck type engines have a powerband of idle - 4500 rpm. It's hard overly increase power in the idle - 2500/3000 rpm range the trick with a street type performance engine is to increase the useable powerband from 4500 to 5000/5500 rpm without losing much and or small gain down low idle - 2500 rpm, higher stall deeper gears lighter car etc... Makes that less important. Efficiency is the third way, mainly low restriction intake and exhaust 'pumping loss' Cr there's others but those are the main. So it's about what's more important idle-3000 or 3000 - 5500 and the balance/compromise of the two.

In the above paragraph, your stretching the rpm range and unjustly assuming his targeted goal of what rpm he wants to perform in and the stretch is very wide and not a balance between a RV cam and a mild cam just above it but way beyond since you labeled the rpm range.
3K-5K? Seriously?!?!

And more direct to your question cam has the biggest role in this.

Above you listed that last.
“Now for RV basically doesn't mean more torque but where torque is made, ”
But it’s the cam keeping the valves open for more cylinder filling.
How is it not the cam that is important?
Changing the stall, gear ratio and tire size helps in a lot of areas just through math alone. Better torque release. You didn’t help the engine power.
Are you sure about what message your sending?
Do you even know what your talking about?

 

[PScamp74]

An “RV motor” or “cam” is just a small cam that is slightly larger than stock in duration and lift to help make more power.

How well will it perform in your car is a Compilation of various items you did not list. We would need a crystal ball (an actual working Chrystal ball that is) to know how it will do in your exact car.

You ask another question that contains what I guess is slang of which I have no idea what your talking about when you said, “but generally speaking wouldn't it pull the tires off of it just the way it is?.”

I don’t know what your asking here. “Pull the tires off of it?”
I don’t know what that means, or what your trying to say or ask.

(Edit, grammer, whoops!)

Well I'm simply asking if it will have great take off torque...I know you all lost me a long time ago, I don't know anything about all the complications of cams and advance and retard and now I feel even more like one. Simply put, I plan to just put the 440 into the '73 Charger SE as it is, running already..I have a very limited knowledge of motor building, it's my uneducated, wondering mind that "figures" if it pulled something considerably bigger ok, then it should "pull the **** outta this car" just as it is.?? A very uneducated engine building take on it.

 

[rumblefish360]

In a word, YES! The 440 moves the Charger well, it’ll do a better job moving the Scamp and do it easier.

Look on the Scamps and Chargers reggie to find the weight of the two cars. For every 200 lbs, consider it like you threw a friend out of the car and the performance will pick up a little bit each time.

So, if there’s a thousand pound difference, that’s like loosing 5-7 average-ish people from inside your car. At this weight reduction level, it will equal approximately 1/10 quicker in the 1/4 for every 100 lbs. Or something along the lines of 50hp per person that leaves the car.
These are loose terms but accurate enough for the generalized discussion we have on hand here.

 

[273]

Yes it is, it’s all about the torque. The idea of the “RV” cam was help more easily move a heavier vehicle.

My point was it's hard to get any decent increase over stock low power cam idle - 2500 rpm, not torque ain't important but where it's made is more important .

Not exactly correct ether. Never mind the values of torque you place on the displacements. For one it’s to general. Second, it’s misleading. The main focus of the “RV” cam is to increase the amount of air and fuel to make more power for more torque no matter the size of the engine. While a bigger engine “should” make more torque, this is not the actual case since depending on the year, some small blocks out power big blocks. During the dark years of the first introduced emissions standards that cut power dramatically during the era which spans from ‘72 on up for decades, even the big blocks were struggling to pull and push around small campers. Hence the introduction of the RV cam & as suggested by name, to help the RV vehicles.

Torque per Cid matters cause the amount a RV type can make is pretty narrow 1.1-1.2 lbs-ft per Cid over 1.25 is usually a well put together street strip type build and under 2500 rpm don't matter.Even getting over 1.15 would be lucky in most cases And a lot of the gain in torque will 4bbl and exhaust.

I probably should of broke powerband into 3 idle-2500 2500-4500 4500-6000.
And saying try to build or least not lose much idle - 2500 while focusing on mainly 2500-4500 while gaining useable range into the third but with least focus. For most street type builds.

While volumetric efficiency has a big roll in power production, it’s not the most easily fixed with OEM / stock parts. The OEM parts only work so well so you just increase the amount of time the valve is open to fill up the cylinder a little more.

filling the cylinder more isn't that ve ?

Mostly wrong. While the improved torque is the goal, below you over estimate and push the camshaft as if it was pushing the rpm limits beyond its basic usage description. This is so not the case.

Being the OE camshaft is very small in most cases never mind the big 114 LSA’s, the RV cam (normally) narrows the LSA, increases the duration a minor amount as well as the lift.

The rpm band of the cam barley increases any meaningful amount.

In the above paragraph, your stretching the rpm range and unjustly assuming his targeted goal of what rpm he wants to perform in and the stretch is very wide and not a balance between a RV cam and a mild cam just above it but way beyond since you labeled the rpm range.
3K-5K? Seriously?!?!

Yes I could be unjustly assuming he cares about above 3k performance, but if he does maybe it will helps him but if not could help others reading this thread.

Above you listed that last.
“Now for RV basically doesn't mean more torque but where torque is made, ”
But it’s the cam keeping the valves open for more cylinder filling. Changing the stall, gear ratio and tire size helps in a lot of areas just through math alone. Better torque release. You didn’t help the engine power.
Are you sure about what message your sending?

My point about stall gear etc.. You could not worry so much about idle-2500 if one so chooses when picking a cam and yes that would not be an RV cam now.


I appreciate telling why you disagree or find me wrong then using and X or just say wrong. Definitely I'm not an expert but it's my take on it.

 

[PScamp74]

In a word, YES! The 440 moves the Charger well, it’ll do a better job moving the Scamp and do it easier.

Look on the Scamps and Chargers reggie to find the weight of the two cars. For every 200 lbs, consider it like you threw a friend out of the car and the performance will pick up a little bit each time.

So, if there’s a thousand pound difference, that’s like loosing 5-7 average-ish people from inside your car. At this weight reduction level, it will equal approximately 1/10 quicker in the 1/4 for every 100 lbs. Or something along the lines of 50hp per person that leaves the car.
These are loose terms but accurate enough for the generalized discussion we have on hand here.

Alright alright, I can relate to that..pol

 

[273]

Well I'm simply asking if it will have great take off torque...I know you all lost me a long time ago, I don't know anything about all the complications of cams and advance and retard and now I feel even more like one. Simply put, I plan to just put the 440 into the '73 Charger SE as it is, running already..I have a very limited knowledge of motor building, it's my uneducated, wondering mind that "figures" if it pulled something considerably bigger ok, then it should "pull the **** outta this car" just as it is.?? A very uneducated engine building take on it.

And if you do any mods just keep it on the mild side.

 

[rumblefish360]

Filling the cylinder is more VE

This is also for the new to engines guy, PScamp74

Not exactly. It is though. The VE is limited by the intake tract (mostly) from carb to valve and will hit a ceiling (mostly) by how much time the valves are open. Let me put it in another way.

A bigger cam allows more in this increasing how effective the engine runs in terms of more power by a greater cylinder fill. But the parts themselves hav not changed.

Valve diameter for door size
Valve Lift for how wide the door opens
Duration for how long the door stays open
CFM for how fast people can go through the door

The door is 1.78 (1.78 feet) wide.
It’s enough for one person to go through EZ enough.
The door only opens up enough for 1 person to get in at a time, let’s use stock valve lift as how wide the door opens in feet. .400, am so half a foot. Plenty for a thin fella to get through.

Now the door stays open for a short time, this is duration and we will use seconds for degrees. In a stock cams case, 198 (or so) seconds. They walk in at a rate of 125 people per event of door opening time.

This is the amount of volumetric efficiency of this scenario.
(We’ll call it a stock 318 head)

Increasing the volumetric of efficiency of the system can not be done since the actual parts are cast steel but you can increase the cylinder fill but rearranging the previous perameters of the door openings with a wider door opening that lasts longer. And here is the beauty of a wider door, it not only allows more people through the wider and loved door openings, but it allows the people to move through faster since there is less chance of hanging into the door. The equals to a cylinder head being able to flow more air and fuel via a higher lift since the port can allow more air and fuel. The change in efficiency is as only as great as the door or head port allows.

To suggest to someone that you have to change the efficiency of the engine isn’t a good idea because of how it’s worded and what you said earlier and as well as what you said the person should be after.

Changing the cam is taking advantage of what is there already and not altering the efficiency of the parts already there but simply just taking advantage of what’s there to fill up more of the cylinder.

In a way, yes it does create more efficiency but only within its limits as cast. Otherwise it’s porting heads, replacing bolt on parts.


So with this, how is the cam not important and making more power? It’s allowing more people through the door! But only an amount to slightly alter the power curve by a few hundred rpm.

This works on any displacement engine. While a bigger engine is better at specific torque output, there is t a need to suggest a engine swap be done or major over hauling or ported parts be done.

The idea of a larger camshaft is to create more power and this is torque!

 

[Righty Tighty]

Thanks for that analogy, very helpful for a novice like myself.

 

[Cudafever]

rumblefish360, for some one that done have a clue as to what a cam does. BROVO!!!!!!!!!! GRATE EXPLANATION!!!!!!

 

[rumblefish360]

Thanks gents.

 

[PScamp74]

rumblefish360, for some one that done have a clue as to what a cam does. BROVO!!!!!!!!!! GRATE EXPLANATION!!!!!!

Bravo bravo

rumblefish360, for some one that done have a clue as to what a cam does. BROVO!!!!!!!!!! GRATE EXPLANATION!!!!!!