I may have to pull my heads for a valve job soon. Will the GT 40P heads go on an all stock '84 GT and work with the stock 4V intake and exhaust manifolds?
you can use several different headers. The P specific headers are expensive but I think mac LTs will fit. Dont try equal length shorts. Dont know about regular shortys
IF you need new headers, stock mustang 87-93 tubular shorties supposedly fit just fine, and they can be had for free.
they will not just bolt up to the stock exhuast tho, unless you have changed that out for the 86 and later setup......be good to do it all if you can tho, get the double hump x member, the 87-93 h pipe (with converters if you gotta smog check) and any old cat back system for an 87-93 LX stang.
I did all this on my 82 RS capri many years ago (sans the gt40p heads of course )
The 87-93 stock tubular headers will not work. I rebuilt my engine with P heads and cannot drive it yet because I have to save up for the headers. The passenger side was perfect, but on the driver side two of the plug boots are pressed against the header.
Check Jegs or Summit for the headers you need. In Jegs they are listed as 5.0L and GT40P specific headers but in Summit they are just listed for 5.0L's. Check out the part numbers though they are identical. Both catalogs list them for $239.
I had a feeling it would have very small runners. I have been thinking of converting the car over to a FI setup in the future. One set of headers that look like they may work are the Ford Racing Parts High-Flow shorties. If so, they are supposed to connect right into the stock dual exhaust system.
maverick0716 said:
That 84 4V intake will choke the heads big time. I wouldn't expect huge gains if you're going to keep that intake on there.