Originally Posted by fast68plymouth
The reason I asked about whether or not the 9.35:1 was the original CR target is........ it seems like the cam duration might be a tad long for only 9.35:1.

With the restricted intake and exhaust, combined with the modest CR, the running dynamic CR starts to taper off pretty quickly once the limited airflow really starts kicking in.

Sometimes running a little less duration will spike up the peak TQ numbers, and if the shape of the curve after peak(same drop in tq/rpm) is maintained, it can yield a higher peak hp number.

I refer to that as, “start high......end high”.
It’s usually only applicable to the types of builds that peak pretty early and make more tq than hp....... which are basically always airflow limited in someway or another.


Dwayne, the compression ratio is the original target.

If I'm understanding you correctly, if the cam had a little less duration, it would potentially pick up peak torque and HP and carry the gains for a little longer? Would that be less duration on both intake and exhaust? How many degrees smaller are we thinking? How much of a gain are we thinking? Also, I know this is all a guess, but what are your general thoughts? I appreciate your input and always like the opportunity to learn.

Dyno.jpg
Last edited by parksr5; 09/14/22 09:35 AM.