[cougar1]

Ok here goes.
old set up...302 2v heads, 650 holley, stock 4 bbl intake, headers, 2"exhaust, crane cam 218/230 @.050 w/488/498 lift, 4 speed and 3.00 rear end.

New set up. Same bottom end, carb and intake. Now has 4v heads so a little more compression, 2.5" exhaust, and comp cam 230/236 @ .050 w/520/523 lift. Same trans and rear gears.

Ok, so why is the car slower now than before? I'm thinking the rear gears. If so why would the car be faster with, say, 3.55 gears with the new set up as opposed to 3.55 gears with the old set up? Hmmmnn Thanks in advance for any answers or ideas.

 

[wvcat]

Slower?

I think what has happened is that you have moved your power band to a higher rpm. Its kinda like a 2 stroke dirt bike now, you have to get the motor in the power band. The rear end gears will make a big improvement. Also with the 4bbl heads you may have lost low rpm intake velocity and a lower gear will also help out with that. My cam is has slightly more duration with a similar lift and my car starts making power around 3000. You may need to fool around with your timing, the stock specs can pretty much be thrown out the window once you start changing cams.
Good Luck
John

 

[cougar1]

That's what I figured happened. The power band has been moved up by about 500rpm. I didn't think about the low rpm velocity thing with the heads. The timing is already set at 17 degrees initial (doesn't ping with 93 octane). I an electronic ignition box and distributor guts from a '77 monarch about 15 years ago.

I guess the car would not be quicker with 3.55 gears and the old set up, would probably end up being 'over' the power band of the old crane cam.

Thanks for the imput,,anyone else?