Custom cam grind question

When you order a custom cam it means they simply select the most appropriate lobe size/shape from their catalog and phase the intake and exhaust to suit your application.

Any camshaft's lift is limited by it's duration. higher duration can allow for higher lift.

try to think of a cam's lobe like a pile of sand.. it can only be so steep. it quickly gets to a point where if you want to make it taller, it's going to have to be wider too.

If it's too steep it will wear out prematurely. Some high end camshafts have this in mind so they can make phenomenal power for a very short amount of time.

Off the shelf street lobes are usually made for a good compromise between performance and longevity.

Mopar engines have a larger lifter bore at .904" which increases contact patch on the cam. we have potential for approximately 7% more lift per degree of duration than a SBC camshaft but this can be strenuous on rocker gear. especially with a factory block's 59degree lifter angle.

You mentioned dynamic compression ratio. This is largely effected by the lobe separation angle. here is a basic comparison of wide and narrow lobe separation angles.

Wide - Lowers dynamic compression, decreases piston to valve clearance. spreads torque more towards lower and higher ends of the rev range at the sacrifice of some mid range torque. reduces valve overlap and therefore provides more idle vacuum and a smoother idle. A typical wide LSA is 110-116.

Narrow. Raises dynamic compression, increases piston to valve clearance. provides more peak torque at the expense of lower output at both ends of the RPM range. more valve overlap means less idle vacuum and a rougher idle. A typical narrow LSA is from 106-110.

Duration is simple. More duration moves the torque curve higher in the rpm range and create more overlap which will reduce idle quality.

true dynamic compression ratio cannot be calculated without knowing specifics about your cylinder heads and intake setup due to something called "intertia tuning", basically this is the very real phenomenon that occurs in which an an engine's ability to breathe and the port's cross-sectional area largely determines "how much" cam is needed to make it perform optimally.

But as said above, the more information you have about your entire combination and your desired result the more likely that a cam manufacturer can help you pick the cam that is going to have power where you want it and as much of it as possible!

The most important thing being to measure your static compression ratio accurately. if you tell them something to the effect of "it's got 10:1 pistons in it" they're going to know that it's probably nowhere near a true 10:1 and give you a conservative cam. Just an example but you get the idea.