AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 24,849
- Reaction score
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You nailed it man,In decades of engine building, I haver never seen a 0.010" spread [ 0.010 int, 0.020 exh ] in valve lash for a street engine. Usually 0.004" at most. If the correct lash is actually 0.020" [ likely ] for the intake, then your comment about the feeling of extra load on the engine makes sense. The tighter lash increases duration, & at low rpms [ lugging ] that often reduces torque, making the engine feel sluggish.
I have had very good results with .013/.020. The low-rpm torque increase was very obvious, and significantly more than I had anticipated. Increasing the exhaust to .023 did not make as dramatic, an improvement, but it was noticeable.
I was after fuel-economy tho, lol. So cylinder pressure is what I was looking for. I think I got 5psi outta that deal, hard to remember cuz that was 1994.