Head swap

[chilsam]

Will 4.0 heads work on 2.9? Have 4.0 intake & exhaust manifolds.Is there a diff in deck higth "ie distance between heads" THANX!!

 

[AllanD]

Yes, the 4.0 is to a 2.9 as a 351windsor is to a 302.

The Deckheight is raised 20mm.

So, no the heads/manifolds won't work.

The Exhaust manifolds would bolt right up but then your Y-pipe would no longer fit.

The 4.0 with it's higher deck uses exhaust manifolds that "hug"
the block a little tighter so that BOTH the 2.9 and 4.0 bolt up
to the same Y-pipes...

I believe ford played the same trick on some F-series trucks with the 302 and 351
This information is "useful" because in something OTHER than an F-150
using 351 manifolds can make a 302 fit easier into a tight engine bay.

AD

 

[chilsam]

Thanx!!

What about just heads off 4.0 ,2.9 is an mfg/88 4.0 is 91. With 2.9 would coolent passages be on bottem or side of head? Sorry if I ask 2 many questions I believe knowledge is power Ive only worked with 300 & 460s in the process of putting the 91 sb ranger bod on 91 fs 300 e4od bronco chassis wheel base diff is only 1' + r - wish me luck! THANX 4 your time n knowledge!

 

[AllanD]

No, the heads are similar, but not nearly similar enough to make them work.

AD