Quote:

Rocker shaft shims are for correcting incorrect rocker arm to valve tip geometry not for setting lifter preload.



But they do the trick when you have block and heads milled. As long as the rocker tip hits correct you can get by with them on a mild build. I proved it in my old 383 Dart with stock non adjustable rockers. It was done on a very tight budget and thats why I did that instead of buying adjustable rockers. It was a mild .484 cammed 383. Like I said I drove it for 7 years and ran 12.30's @ 110 with it. I only had .025 of shims under the shft as there is a limit on how much you can go without messing up rocker geometry. Ron