Originally Posted by AndyF
Did you measure valve drop at TDC? I always keep track of valve drop since it gives a baseline to work against if I decide to change cams. Also, on you PV measurements are you using checking springs or the real springs? Real springs add some clearance since everything bends away from the piston.
I have never tried to push the valve down to the piston with real racing valve springs installed. As far as valve drop, I measure the cam lobe lift at TDC (and other positions) and the piston to valve clearance at TDC (and other positions); so I have the information you need to compare to other cams. See the tables I have posted.
It is nice when some cam vendors publish the lobe lift at TDC. Even though it only applies to a certain installed lobe centerline.


1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1