antwaan

I haven't drove my 96 Mustang GT much over the past few years. I'm working on fixing it up and would like to do a PI swap. It has around 135k miles on it. I did a compression test on it and here are the results:

C Dry Wet
1 155
2 150
3 140
4 150
5 145
6 85 90
7 105 105
8 150

So it seems I have good compression on everything except 6 and 7. I also did a wet test on those two and it barely moved the needle. I don't have coolant in my oil but I am assuming it still the head gasket being bad causing the low compression. I have noticed if I punch the gas in say 2nd gear, once I hit around 3k-3500 rpms it will start to miss and cut out, if that's related. If I do the PI swap, it will of course get new gaskets. Should I look for anything else before I snag a set of heads and the rest of the PI swap parts?

Derf00

A wet test only really tests for piston rings. If the rings were bad you'd get higher compression because the oil would act as a seal.

To find out the real problem you need to do a leak/down test. That will help you see if its a head gasket, valves (intake or exhaust) or a crack. Guess it's a blown head gasket between the 6/7 cylinders since you have no fluids mixing or bubbles in your coolant (?).

08'MustangDude

IF you are doing a PI swap, then why bother asking about the head gasket, since
all that will be replaced when you do the PI swap... Valve-train, same thing, this
is all MOOT since you're doing a PI swap anyway.

If there is no oil and coolant mixture, then either the gasket blew between 6 and 7, as
stated, or you have valve issues, or the compression rings are bad on those two.