And, just to throw another wrench into the works.....

Since you'll be pulling some springs to use the height mic anyway, I suggest you carefully test the spring pressure first, and make note of the pressure and the installed height for each.

Then bring those springs to a shop with a quality bench top tester(preferably a shop that also has a calibration spring), and see how their results compare with yours.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads