Originally Posted by 440Jim
Originally Posted by fast68plymouth
It’ll be interesting to see how that cam works at the top end of the curve.

Do you expect the large duration split to improve or reduce top RPM power?
I do wonder if the "small" 2-inch dyno headers (which may be longer than 30"?) will reduce the top RPM power.


I don’t know that I have an “expectation” on what it will do.
This motor has slightly bigger heads than a 580 we had on the dyno a couple years ago.
It also should have better oil/windage control, a better intake manifold, and more throttle body capacity.
The one here had a couple more degrees of intake duration, but less split.
It didn’t make anywhere near 900hp, but we weren’t expecting it to either.
Peaked at 64-6600, and didn’t really drop off till 7k(down 20hp).

I’m interested to see where the TQ peak occurs, and then how flat the HP curve is at the top end of the pull.
Basically....... can the big split help cover up for the smallish intake/exhaust ports for that displacement?

If it had “big” heads, I’m sure that trend of the extended top end would be there....... but not sure what to expect with the smaller heads.

When the induction isn’t the cork in terms of where the peaks should occur, the big split can really help move the peaks nicely up in the rpm band.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads