Originally Posted by stackitup_91
I am in the process of doing a SBC build. I have a 350 bored over .30, I went with a 2 valve relief float speed pro piston which put me at 10 to 1 compression with a 64 CC head, I have a set of modified Vortec heads ( the guides have been cut and I have a new springs that hold up to 575 lift, new guide plates and screw in studs, 202/160 valves, and heads have also been ported and polished). as far as the camshaft to goes I have a XE284 comp cam 507/510 lift 2300-6500 is the rpm range on that cam, I have full roller rocker arms 1.6 ratio from comp cam, new floating eagle rods 5.7 length, Shorty Hooker Headers 1 5/8 3 in collector with Flotec muffler, the crank has also been polished, I have a Holley 650 double pumper carburetor and rpm air gap intake.
the car is a 84 Z28 Camaro with 700r4 transmission with shift kit, vette servo, and I just purchased the 3000 stall for the transmission, for my rearend I have a 7.5 with 3.73 gears posi traction.
I am only going to drive the car once or twice a week, how much horsepower and torque do you think I will be putting out at the wheels? how well do you think this setup will work?
I don't know about horsepower at the rear wheels, this is extremely variable to the point that I think relating crankshaft dyno to chassis dyno numbers is voodoo science at best. Most chassis dyno guys like to sell a 20% or so hp loss between where the tire meets the pavement and where the crankshaft meets the transmission input shaft. My experience at Ford many years ago show that number can easily be close to 50 percent. So at best you're looking at a range that carries up to a 2 times the differential. Very small sins of installtion can carry very high power loss price tags. If you have a crankshaft and chassis dyno numbers then you can go to work on the where the losses need to be rectified. Most guys immediatly react by going back into the engine when the problem can be with the installtion, a turn just a little wrong in the exhaust, a binding or off center u-joint, a little excessive deflection in the tire, a dragging clutch in the posi; it just doesn't take much to really push the numbers around.
Basically the parts you have could easily make 400 plus horses at the crank but you've got some limitations on the engine before getting there. The headers should use 1-3/4 tube and be full length. The XE284 cam carries a lot of overlap which will respond very well to the aggressive tuning of long tube headers. The carb needs to be bigger say 750 CFM this thing will want more air flow than you think and that calculators would predict.
The 7.5 inch rear axle puckers my tail. That thing isn't up to this kind of power. It certainly would be a bomb waiting to go off with a stick gear box, it might last a little better behind an automatic depending on how hard this thing shifts with the mods you did to it. Harder shifts beget more shock load on the driveline. That small ring gear ain't gonna be happy with that.