Does anyone know the correct valve lash for a 70 LT1 stock cam / heads etc. It does have 1.5 roller rockers, but 1.5 was the advertised stock rocker length (although it is known to be closer to 1.37). Anyhow, I have read 24, and 20. An old timer said 8, then he said you could go to 18 - "the looser they are the better they run". As a engineer, I tend to lean towards specification, does anyone know the real specs?

For the 70-71 LT1 3972178 cam, I have .024".In / .030".Ex.

John

John,
Great information, where did you find it? Got a link?

Frank

I found it in the GM Performance parts Catalog. If you just want it stock that spec will work, but if you want the most you can you should try it a bit tighter to see. Mine made a 10 hp difference with .010 tighter lash. Yours may or may not like it. That is the beauty of a solid cam you can adjust lash and tune some of the power of the engine.

I found it in the GM Performance parts Catalog. If you just want it stock that spec will work, but if you want the most you can you should try it a bit tighter to see. Mine made a 10 hp difference with .010 tighter lash. Yours may or may not like it. That is the beauty of a solid cam you can adjust lash and tune some of the power of the engine.

Those specs are correct and yes,I got them straight from the GMPP catalog as well.Got them hanging on my garage wall.;)