Hello everyone I am new to forum. So my question is that I just added gt40p heads to my 1991 f150 5.0 2wd shortbed. I picked up long tube headers off Craigslist but when I try to install them the passenger side the top of header sits flush on head but the bottom does not due to fact it hits trans where starter bolts up. I know the plugs are oriented diff on these heads but is that it? Anyone else hear of this happening or maybe the headers I bought were for something else. Trying to get some insight before buying new headers

 

The plug angle had nothing to do with the headers hitting the transmission. You bought headers for a different application, probably those meant for a car with a 157 tooth bell housing. You're going to have a difficult time finding headers for your truck that also fit the P heads.

 

Thanks I know the plug angle isn't the issue I was wondering if there were any other diff. In the heads. After looking over the headers I got a part number and they come up as 5.8 headers. Not sure why they would hit that part of the trans though. Only paid 20 bucks for them so lesson learned. Thanks for your reply

 

The 351W is taller and wider, that's why the headers don't fit. They come off the heads at a different angle because of that, that's why they didn't clear the bellhousing. Lots of times 302 headers will fit a 351 but the other way around is hardly ever true. Headers for a 351 have to hug the engine closer to clear the frame rails. 302 headers on a 351 would hit the rails instead of the bellhousing.

 

If you know some one good with a torch you can try and flex them over. I you have a good steel work table bolt or clamp them down, heat the tubes and then try to slow bend them over just enough to clear.

I does sound like they are for another application though, but I think just a little heat and you can make them work. Just try to do a little at a time so you don't kink your pipe.

 

Thanks guys. That totally makes sense on the wider 5.8. I just ordered some new ones and will recoup my 20 bucks by putting them back on cl.

 

Yeah you need headers made for these pickups specifically.. not just the engine. I have used the same longtubes on 5.0 and 5.8 motors in these trucks so they're not that different.. I suspect you got Mustang headers or something.