What is the stock compression Please help.
 

Hi I have a 91 GT 5.0 and I'm wondering what should my compression be at.Thanks need to know fats going to run the comp test in a few hours.

Are you referring to cylinder compression, or cranking compression? Are you just trying to get a number to shot for while running a compression test, or are you trying to figure out cc's?

In either case, you need to give up more info. What's been done to the engine, how many miles, etc.

If you are running a compression test, make sure you know how to do it. If you forget some of the simple things, like having the engine hot, or blocking the throttle open, etc., the results will be all wrong, and will be meaningless.

Take care,
~Chris

I have nothing accept headers and a k&n air filter on the engine. I ran a compression test on the cylinder heads and the pistons and valves. I'm just wondering what a car with 180,000 compression would be on those things.Thank you

Okay, let's try this a different way. Why don't you tell us what the readings were that you got. List all 8 cylinders.

Take care,
~Chris

All I wanted to know is what the stock compression is not what mine should be. thanks though I had 150 on all 8 w/ 180,000 miles.

150 is good, and being even all around even better.

Skyler

If the test is done properly, at sea level, a stock engine with 180k on it would be doing very well to have a 150 psi average, dry. Wet it could be over 165+.

Take care,
~Chris