Replacement head recommendation requested

[skipilot54]

Hi Guys. I'm running a carburrated 1995 PCM PLD 260 hp Ford 351w with 2 bar cylinder heads with casting No FE3 JE CA. Its raw water cooled and 1 head is leaking water from thermal stress crack in water jacket running across three cylinders. This was due to incorrect head gasket fitment in the past, not freeze damage, and my local Nautique dealer has said that this was a common problem on this head.
I've been unable to find any 351w replacement marine heads for this engine but have found some off a 302 with the same casting number.
Is the only difference between the 302 and 351 heads the increased (1/2") bolts used on the latter. If I get the bolt holes drilled out will these heads work as a direct bolt on replacement?
My other choice is to use Marine 3 bar GT40 heads. Same question. Would these be direct bolt on replacements?
Is there a better or cheaper option going with re-manufactured cast iron auto cylinder heads - GT40P?
Your recommendations and suggested supply source would be welcome.
Thanks in advance.

[2001SAN]

Same heads. GT40s including GT40P are all useable. marineparts.ie in Dublin had some standard heads in stock a few years back but they were not cheap.

D.

[Fgroce]

Hi too bad about your head cracking, The last model P heads are a definite improvement over the originals, some say they has slightly better performance than the original GT40 heads. The only difference is the the exhaust ports are slightly raised. Other than that they are an exact bolt on. There is a company in the States Promaxx cylinder heads. They make new replacement heads that have gotten good reviews.

[t.franscioni]

Im just going off memory from an article or something I read online but I want to say the P heads had a tighter combustion chamber. If that's the case technically they should make slightly more power than your stock head on the other side so you'd want to swap both sides to P heads not just the cracked one. I'd ask someone with engine building experience about that though just to make sure.

[gary s]

If you have to source other heads GT40p's would be an excellent choice,the smaller chambers they have will raise compression slightly. Intake and exhaust manifolds bolt up exactly as on your originals,sparkplugs being at a different angle is the only difference. Be leary of GT40 heads they do have external cracking issues and can then leak.Any 302/5.0 head,which P's are,will need to be drilled to the larger head bolt size of the 351 as will the need to use brass core plugs(freeze plugs). Any heads should be replaced as a set but you could replace just one if the same type was used and the original head rebuilt ,you don't want the valves not sealing as well on the old and the correct way to rebuild may require it to be skimmed which may cause that cylinder bank to have higher compression.You can also google Ford small block cylinder heads,there is alot of info on Ford Mustang sites. Correctcraftfan.com will have info if you do a search on the site many have changed to the P's and added an aftermarket intake manifold also.