Hi

I was doing a compression test on my 65 mustang 289. 7 cylinders are between 150 and 155 and the 8th cylinder is 130. Just wondering how bad this is and if there is anything that can be done

This Walter

 

Did you put some oil in the #8 cylinder and test it again?

 

No I didn't. How much oil should I add? Will that help determine how bad it is?

 

Just put a table spoon of oil in the spark plug hole & do the test again. If the compression comes a lot it's likely a ring if it doesn't it's probably a valve problem. You could do a leak down test to pin point the compression lose.

 

^^^ What he said