Does anyone know what the compression is supposed to be? The book I have only provides numbers for the vaccuum.

 

spose between 150-190 psi ...max. variation 20 psi per cylinders

 

9.3:1

 

Looks like it should be around 9 1/2 - 1 from what i have found.

 

This is what the chiltons says...

 

That high? I have a 71 bug and it is 120 PSI - I am just wondering....

 

is it really that cause guess what i found when i took my heads off they were closed chamber heads which should be higher but i could never fig out why my valve spring seats were cast or machined down a tad i had never seeen that b4 on any other 289 heads but they did come with bigger studs than the 5/16 for sure but there was a 2bbl slapped on my car so ya i am thinkin those are heads for a 4bbl or thats just how they did it in 65 cause everything in/on my block is a 65 casting year

 

pressure in Atlanta, Georgia is currently: 1021mbar == 14.8 psi
so if the compression ratio is 9.3:1 you should get 137.64 psi opt in case you're not loosing any pressure anywhere measuring or in the engine ....

Kalli

 

brandon all 289 heads and early 302 heads had closed chambers, if your heads had factory 3/8 rocker studs and the springs are sitting in "pockets" you may want to look further into those heads.... they may be the 289 hi-po but i cant imagine how they would end up on a motor with a 2bbl carb

 

it was a rebuild and it came with the car the intake was from a 67 everything else was 65