How strokers affect how a cam "acts"

elitesrock2 said
Now what compression should i be looking at then? I've always been told 9.4-1 with good quench is the magic number for pump gas. I know theres different types of compression such as dynamic and static

elitesrock2 said
So say my build was 416 stroker with a forged crank 72 cc ported x heads that will take 6700 rpm with a huge solid roller so airflow is not a big issue for my powerband. the comp XR268R camshaft with 268/274 230/236 .552/.564 lift with harlands 1.5 ratio. want to run the 4032 forged icon pistons to have a tighter piston to wall clearance, performer rpm airgap intake and 750 proform carb. What should i put my compression ratio at then? where i am at the temperature varies from 0-100 winter to summer. I intend to run it on 91 octane pump gas.

What I would do, is figure out your cam THEN figure out your static compression ratio. Yes you can build your cam to your current compression ratio but it's going to probably end up being smaller than you want in order to keep up the DCR. You want DCR at 8:1 to 8.5:1. Use: Wallace Racing: Dynamic Compression Ratio Calculator to figure out your DCR.

For example. Say you want to run the XE268R. At your elevation (Spokane - 1800 feet). Calculator says:
10:1 static compression = Your dynamic compression ratio is 7.95:1. Your dynamic cranking pressure is 158.58 PSI.
10.7:1 static compression = Your dynamic compression ratio is 8.52:1. Your dynamic cranking pressure is 173.47 PSI.

So you would want to be somewhere between 10:1 and 10.7:1 static compression for that cam. Quench of course plays significantly into this. Ideal quench is .035 - .040. Better quench = more DCR because you have less chance of detonation. CC your heads. And depending if your pistons are flat deck or out of the hole, you need to adjusted your head gasket based on that.

In the end your static compression ratio depends on your cam. Get your cam figure out, then build your compression ratio.