When I make a comparison in the aggressiveness of the ramps between different cams, I subtract the .050" duration from the advertised duration (usually given at .006) The smaller the difference, the more aggressive the ramps.

51 or 52 indicates pretty aggressive ramps. Of course, the advertised duration of all the cams being compared have to be measured at the same point - .006 is the number I usually find.

With my valve train setup, I used the old "Magic Marker" method to find out what length rods I needed. Based on the variables on my engine, I ended up needing 7.500" pushrods.

I forgot the specific, exact number, but from memory, the stock LT1 head gaskets for my engine are at or just above .050" in thickness. If I come across the exact thickness number posted somewhere, I'll post it here.

Good luck.

Jake

 

I tried several different lengths today with a light compression spring I picked up at HomeDepot as a valve spring so the lifter would not compress any.
I tried 7.40" and the pattern is slightly narrower than the 7.30" but is further out to the outside edge, probably 2/3 of the way towards the outter most edge.
Then tried 7.50" and the pattern as easly 3/4 of the way to the outter most side.
Tried to take some pics but the wear pattern was not very distinct with the light spring in place, could really only see the oil marks from the roller tip rocker over the entire pattern.
Also, the 7.50" makes the rocker when at max lift come very close to the top of the stud/nut, so I can conclude the 7.50" is too long.
Given that, the 7.30" prs I'm running are not the cause of the noise, the pattern is centered on the valve but slightly wider than the 7.40-7.50 lengths.

Did not see any noticable abnormal wear except that the valves do not rotate any when opening and closing, the step tops all have the same wear pattern from the markers several thousand miles ago...
I thought the valves rotated ever so slightly every time they are opened/closed???