what size header 5.0 or 351?
 

I’m ready to install gt 40 aluminum heads on my 5.0 with a new set of headers, but which headers do I buy? 5.0 Or 351 headers?

Re: what size header 5.0 or 351?
 

what car do you have? buy headers to fit your car
if your car is a 5.0 ...just buy 5.0 headers the exhaust ports are the same on 351/302 heads

Re: what size header 5.0 or 351?
 

It’s a 92 coupe 5.0, but most header listings list the mustang with a 5.0 and 351 motor, so I’m not sure if I should purchase the headers for the 5.0 motor or the 351 motor. Because the SVO GT 40 heads are 351 heads.

Re: what size header 5.0 or 351?
 

While the 302W/351W heads have the same exhaust ports, some of the 5.0 heads (P heads come to mind) have different exhaust ports. The 351w block is somewhat taller than the 302W/5.0 block. You will want headers for 5.0 block as mentioned by FatOeknee. If you have "P" heads, then it's a whole different ball game.

Rev

Re: what size header 5.0 or 351?
 

Thanks it all makes sense

Re: what size header 5.0 or 351?
 

351 headers are taller, they'll bolt onto your heads, but won't fit in the car very well at all.

Re: what size header 5.0 or 351?
 

I would have thought the 351w header would work because actually, they run tighter to the engine because of the extra width of the 351.
I know, for a fact, that 302 headers won't fit into a foxbody mustang that has a 351w.