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.
