people, have a tendency to chase a specific horsepower level, which, for racing, once you get into top gear, you gotta.
Read this and skip the rest;
The quickest way to performance, on the street, is with stall and gears.
For a streeter, horsepower per se, isn't all that important. Because, you have a transmission, which multiplies the torque, that makes the horsepower.
For a streeter, that is usually limited to rear gearing that is suitable for occasional highway cruising, yur gonna find out real quick, that you are only ever gonna get to where the power is, just once, before the car will be speeding.
Just suppose you did build your slanty to 200 hp. This would come at around 5000 rpm , or higher.
If you stuck with 2.76 rear gears and 25" tires, with an automatic, THEN, this will come at about 50 mph using the A904 and assuming 10% slip in the convertor.
When you shift at 5000, the rpm will drop to 2950, and the poor slanty, or any engine with a Torqueflite trans, is stuck in slow mode, and won't be coming up for air until say 4000 rpm, which for you, will be 67mph.
So now, your 200 hp engine has been seen only once; and briefly, in first gear, from say 4000 to 5000 rpm, which is from 40 mph to 50mph.
Is that what you want in a streeter?
Well it was sure not what I wanted!
I wanted to smoke the tires in second gear at 50 mph when I pulled out to pass some hiway-tortoise, and I wanted those tires to keep on smoking when I screamed by him/her looking him right in the eye, at 85 mph. Oh yeah. and
I wanted to leave it in second gear in the city, and slide my car around as many corners as I encountered. Great big beautiful drifts, with the engine screaming for mercy at up to 7200 rpm.
For that; 2.76s were out.
And 2.76s will be out for you as well.
So if horsepower on the street is not the target, then what is?
Horsepower is fun, I'm not kidding, but any time the tires are spinning, you basically have more power than you need.
In first gear, my tires will break loose at less than 2000 rpm, still on the primarys; and once spinning, I can slowly close the throttle to just above idle. She will continue churning like that, with the line-loc applied, all the way down to IDK, certainly under 1200 rpm. She's a real crowd-pleaser. The point is this, my engine already has more than enough horsepower at 1800 rpm, to break those tires loose;and whatever more it has, is overkill.
Ok then lets figure this out; Lets say my engine easily makes 20 hp at 1800 rpm to break traction. the formula for making horsepower is
(Torque times rpm)/5250= hp
so to extract the torque from the horsepower, we re-arrange it to look like,
(hp x 5250)/rpm=torque; and so, (20x5250)/1800=58 footpounds.
Ok; But I have a 3.09 low gear in my manual trans and a 3.55 in the back, so the rear axles are actually seeing;
58 x 3.09 x 3.55 = 636 ftlbs, and I have 27 inch tall tires, so the contact patches are seeing (24/27) x 636= 565ftlbs.
Ok then, knowing what it takes to break loose, two hard 295/50-15s ; we could now apply that backwards to your combo.
To make this easy, I'll say your tires are 24" tall, your gears are 3.23s your low gear is 2.45, and your tires are half as wide as my 295s cuz that is all you can fit into your tubs. With half as much rubber, you'll only need half as much torque, so looking for say 300 at the tires. therefore;
300/(3.23 x 2.45) = 38 measely crank ftlbs. Piece of cake! , all we have to do is rev the motor up high enough to find 38 ftlbds, and you will be spinning two 5" wide tires, x 24" tall.
Suppose your slanty makes that at 2200 rpm, then all you need is to install a convertor that stalls at 2200 rpm or more; You don't even have to touch the engine!
And that makes my point. which is this;
The quickest way to performance, on the street, is with stall and gears. This is especially true as the engine gets smaller, and is physically handicapped by things like a low compression ratio, poor flowing heads, a tiny exhaust, and a stinking 1-bbl carb, lol.
Personally, for your combo, I like a 2800 and 3.73s. For about a grand, if you can find gears, for the 7.25, you can be having a blast............ but don't try reving the old girl to 5000. The valvesprings, in my experience, are done at about 4500.
The neat thing about 3.73s and 4500 shift-rpm, is that first gear tops out at about 33 mph now, and second at 56, so your engine is gonna go thru the stock power peak twice!
And the 2800stall will rocket off the line when combined with the 3.73s.
and, the engine is still the anemic, what were they in those years? 145 hp?
So then, one more time, for effect
The quickest way to performance, on the street, is with stall and gears.
