3stangs

will a set of 87GT heads fit a 94 GT and are their any differances.

Black Snake

Yes they will fit, no they will not make a difference, unless you port and polish.

3stangs

planning on port and polish and adding bigger valves. Do you have any ideas for horse power gains on stock heads. I have a recked 87 with good heads and a friend that will do port and polish for 50$ . Now that I'm not spending $1500. on heads I can do extra. WHat would be a good size valve to go with?

vfast

why not drop 250.00 on a set of "P" head instead

95whitecobra

I think 1.78 and 1.54 are the stock valve sizes. You may be able to get 1.90 anf 1.60 to fit, if not than I believe GT40's gave 1.84's.

3stangs

the cheapest I can find GT40p heads are $550.00 . If I use gt40p heads will I need different headers or is their a brand of spark plug that will work with the stock headers. And will all my other stock parts work with them?