What should the cylinder pressure be in my 330/310 engine be?

I've checked and i'm getting 90 psi, which seems low to me

 

Depends on the build but I would think 140 would be a good number...why did you check it...running issues ? The guys here are olds experts...feed us lots of info and we will do what we can to help.

 

It does seem low. Try putting some trans fluid in the cylinder, maybe a teaspoon, and see if that changes it. Is that 90psi on all of them?

 

No, unfortenately it's not 90 on all. Number 7 has 0 psi. The engine started missing badly, so i pulled all the plugs and checked. Found the problem cylinder. All others except 2 have 90 psi, the other 2 have 75 psi. I just bought this baby, so don't know anything about the motor other than it is a 1965 330, but not matching number 65 block.
It is very strong though, high performance cam, solid lifters.

 

somethings not right to all of a sudden go down like that

 

Not good...gonna have to come out...talk to the guys at Precise Engine in Calgary...they have done two for me and they know Olds engines...have done quite a few...

I bought my Cutlass 8 yrs ago with a supposed rebuilt engine...ya right...ran good for a few weeks then it caved...There are a lot of lousy backyard builders out there...Hope there is nothing too wrong with yours...