Ok, don't know a lot about cam specs. Thought I put in a decent cam, but starting to second guess. 454 with 290 heads, performer intake, Edelbrock 750 carb. Runs, but not on the road yet. Street driven car 99% of the time. Cam is the Edelbrock performer. Thought I'd stick with their package. .500 lift, intake and exaust. don't know duration off hand. Can check Summit catalog. My question is, how is lift measured? Seat to seat, or at .050? Don't quite understand the diff., but ran numbers both ways and there is a huge difference. Very concerned. Have time for a cam change before bodywork starts. Also, same cam specs, but roller instead of hydraulic show 40 hp increase. Can anyone back this up? Big expense, I know, but a bigger roller than what I have may be the way to go. Thanks.

Eric

You can enter cam specs on desktop dyno either "seat to seat" or at ".050", but lift is the same for both. It's the duration that changes and is giving you the difference. That cam has a duration of 292/302 "seat to seat", which = 218/228 at ".050"
Roller cams the same size will make a little more power due to less friction between the lifters and cam.

roller cams also cost about $700.00 total to put into a non-roller block ;)

if it were as easy and cheap as a hydraulic cam, you wouldn't see hydraulic cams anymore ;)

[Thanks. That makes some sense to me about the duration. I know the roller cam would be a big expense, but if I was going to change cams, I'd consider spending the extra $$ on a bigger roller.

Eric