Craig, did you use the "Seat to Seat" duration vs the "@ .050" numbers? I have that program too! It shows that if you go by the "@ .050" duration numbers that the results are much poorer. I like it though--good ref material. I noticed that too about the roller cams not specifying hyd vs solid---what's up with that?

Kamma;

I would talk with some of the cam companies on that issue, not some flunkie on the desk either someone who really knows...like a Gordon @Comp or Steve Tanzy @Erson. I'm interested in what they say on the solid flat vs hyd. roller @5600ish as well. Solid flats will obviously kick a hyd rollers ass over 6000. My hunch is the solid flat will make just as much in the 5500-6000 range as well. The best thing is they are unbelievably cheap.

jdnca1, the Desk Top Dyno is suprisingly close (SOMETIMES) to some real dyno sheets I have using the same data i.e. cam specs, carb size, header types, comp ratios, various heads, etc. It's interesting and can be a lot of fun to play with. I will check into Erson & Comp. Thanks

When using Desk Top Dyno, the cam type you choose is defining how aggressive a lobe design you're running more than just the type of lifter. For instance a good hydraulic roller really has a cam lobe more similar to a solid flat tappet than a solid roller. A stock GM hydraulic roller probably more closely resembles a flat tappet hydraulic lifter cam. I generally specify a solid lifter design for engines with aftermarket hydraulic rollers and it works out pretty close.