I am a new user and in need of help. I have a 74 Bronco with a 91 mustang GT engine and Gt40P heads. Any one know of a shorty header that will work? I have heard of mustang guy's using 90 degree plug wires. The bronco part suppliers all say there headers won't work with GT40P's.

Any sugestions?

 

are you sure it has gt40p heads vs the gt40 heads? gt40p heads have the spark plug coming out at a different angle so regular headers won't work. gt40 heads have the same angle as all the others. if someone was going to buy different heads for a mustang i doubt them to be p's.

 

yep, there P heads. They have the plugs sticking more straight out of the head than on a normal ford head. Got this engine from a guy I work with, and he told me what this engine all has. He went with a stroker block from ford for his mustang.

The only other solution I can think of is to use mustang shorty headers for the P heads and reposition the collectors.

 

that sounds like your only option. does he have a set you can try? worse case you can get you one of those u-weld-it kits

 

are there any years of stang headers i should look for, i too have the p heads on a 91 351w. thanks

 

Did you find a good solution? I have the same problem. I actually cut the flange off another set of haeders and used it with another gasket to space my header out, it sorta works but not well it still wants to burn up my plug wire on the number seven cylinder. I was just wondering if you have found a better solution?

 

haven't got mine yet but i've been led to believe that frpp has mustang heaqders under two part numbers. that will fit. both shortie, part numbers,
1. m-9430-p50
2. m-9430-p51
not sure of the difference, but quote unquote they will fit. good luck

 

yes both of those part numbers work with the P heads, and on a 74 bronco that is probably your only choice but for future reference on other ford trucks the regular headers will work because they come out farther before they turn down with the only problem is the #6 plug, you have to remove the headers to get to that one, and watch that wire as it will be fairly close I used 90deg wires though, and it worked fine.

 

what do you mean by regular headers, i have a 351 w in a 91 4x4 supercab with the gt40p heads, what will work besides the frrp headers i mentioned? the mac 302 equal length headers i had on before the 351w swap won't work well #6 close fit but can change plug with them installed, but the #7 is where the real problem lies, even with 90 degree boot, boot just touches the header. i haven't seen any long tube headers for these, but i think they would work as long as they can be hooked up to the single cat back i have. hope you can send some advice, would be nice to solve this with some easier to obtain headers, the frrp ones are expensive and special order. thanks!

 

I was running headman headers on my 86 F150 4x4, and they worked with the problem of #6, so I guess I should have made that clear that was the type that worked on mine, and that was on a 302.

 

these were shorties, equal length? how did the #7 boot fit? i have a 351w so there might be some interference with the shifter rod, but then maybe not. do you have a part number for these? thanks

 

I assume you are talking to me so the part number was headman part number was 89350, on summit just add hed-89350, they were just your typical long tube header for my application which was an 86 F150 4wd 5.0, they also make them for the 351w under part number 89270 same applications, and the #7 boot fit fine it was only the number 6 that was close, but it still fit without bending the header tubing, main reason I noticed it was I ddin't get the plug on all the way once, and it burned the boot, plus like I said I had to loosen the headers to get that one plug out.
BTW the 89270 headers fit 82-95 F150 4wd 351w here is a link to the summit page
http://store.summitracing.com/defaul...23429&x=14&y=9

 

do i need to run dual exhaust with these headers? and thanks again

 

they are full length headers but I suppose that it would depend on your exhaust shop if they could figure out how to do a crossover, but basically you can run dual aor single with any header is just a matter of bending, and fitting a cross over to hook into your current system, and for the difference in price for the frpp headers I think that you would be able to afford that easy enough.

 

yup, thanks