GNJ

I degreed both my 502's and set the ICL at 106*. That I'm pretty sure of.
I am using ZZ502 cams and changed my exhausts to dump the water farther down the exhaust because i was getting reversion. Cam info:
.527/.544 110* LSA
Duration 224*/234* @.050
My degree wheel seems to have an indicating range of EVC which goes from 20* to 60*. At 106* ICL, the EVC on the wheel shows 74* ATDC.
When I plug the cam info into the desk top dyno, it says the EVC should be 3* ATDC. Why are these numbers so far off from each other? Am I missing something here?

Vinny P

This link from Comp Cams explains the degreeing procedure well. On a side note, although your duration is not that radical, that 110* lobe seperation may be too tight for wet exhaust not to revert.

GPM

Your cam card numbers are probably at .050 lift and your desk top dyno is probably at .0 lift.

GNJ

AHHHH! Thats right! Thanks GPM. I never received a cam card on the ZZ502 cams, but I did make the mistake and put the duration #'s in the desk top dyno based on .050.
Do you or anyone know how to convert duration numbers @
.050 to seat to seat?

GPM

The numbers would change by ramp speed, you could check it in the motor with a dial indicater and a degree wheel.