67 Firebird I recently bought has a 69 400 block running #18 Heads.
Compression is 180 PSI on 7 of 8 Cylinders. #1 Cylinder is 92PSI. Squirted some oil into the chamber and PSI stayed the same. Pressurized Cylinder when at TDC and air coming out of the Carb so figure #1 Intake Valve is leaking.
Going to pull valve covers and adjust / reset the lash on all the valves and see specifically if that helps #1 Cylinder.
Question: Before I dive in does anyone know if #18 heads had press in studs or adjustable? Did a look online and there are several ways to adjust lash but dependant on type of stud. i.e. torque to a specifc lb/ft or tighten till push rod just stops from being able to spin then go 1/2 turn more to same but use feeler gauge (car paperwork shows a Crane Cam saying set minimum .040" min clearance between the underside of the rocker arms and the top of the retainers after valve adjustment.) If that is the spec for the Cam I think I'm safe assuming they put in adjustable studs otherwise how would you go to a specific torque and still get 040" min clearance?
