Cam recommendation - https://www.summitracing.com/parts/cca-35-255-5

You will need appropriate valve springs and push rods to match the cam. If you are looking to keep costs down, the cam is the best bang for buck upgrade you can do. The next place to go is improving the exhaust.

 

I did something similar with my 95 F150, albeit with a roller block. Autozone has lightning GT40s fully dressed for about $250 each (before core). The downside for you is they do not have provisions for the AIR injection. They bolted up directly to my F4TE block without issues as they already have the larger holes in the head. I did springs and roller rockers with the comp 35-512-8 roller cam ( i think there's a flat tappet version as well).

 

I hate to awaken an old thread, but I found some 3 bar GT-40's for what I thought was reasonable. I was told these have the smog provision, can anyone verify?

 

What do you mean "Smog Provision"? I don't see any thermactor Ports, if that's what you're talking about.

 

I'm not really sure the right definitions of what I'm looking for. If its thermactor or not. What would I need to do to make these heads work on my 88 351w, stay smog legal, and keep my existing emissions system? I apologize for my ignorance in advance.

 

I don't rightly know, to be completely honest. It somewhat depends on where you're at, and the emissions regulations. To the best of my knowledge, you can plug the thermactor ports on heads that have them, and remove the "wishbone" off the back of the heads, and it will still pass emissions just fine in most states.

But that is by no means a guarantee. Hopefully somebody else that knows better than I do will chime in.

 

Those are not set up for the crossover tube if that is what you are asking.

 

I see, would that be at the rear of the head? Can you reference a picture of what I should be looking for?

 

The hole with the threaded insert is the hole that your GT-40 heads lack. In stock applications, they would be connected to what I call a "wishbone"

It will look something like the following image, and hook to the back of both heads, and be connected to one of the outputs coming off of the smog pump.


That probably isn't exactly the right one for a Windsor (or maybe it is, I just found a representative image), but it should look similar.

 

Thank you for helping me understand that, now I know what to look for. It looks like the heads advertised as "1987-1995 Ford Mustang 5.0L Ford Racing GT40" heads have the thermactor hole. Do these have the angle that would work for a 351 like the GT40 non-p? What vehicles would these have come on? Just the stang or explorers/mountaineers too? If found would it be wise to grab the upper and lower intake too? I know the most desirable set would probably be the heads and upper and lower intake from the 5.8 lightning but probably unlikely to find a good reasonably priced set especially where I'm at (socal).

 

Yes. Those will work fine on a 351W/5.8. In most cases, physically there is *zero* difference between a 302/5.0 and a 351W/5.8 Cylinder head, dimensionally (with the exception of oddballs like the GT40P, TunnelPort, Boss, and some other heads). They're on the same bore centers, and the head bolts, Exhaust Ports, Intake Ports, and accessory connections are all in exactly the same places. The only differences between a 302/5.0 Head and a 351W/5.8 Head, in stock applications is the size of the holes for the Head bolts. The smaller engine uses 7/16" headbolts in the vast majority (possibly all of them, I don't actually know), and the larger uses 1/2" headbolts.

Obviously you are going to, in general, see smaller combustion chambers, and possibly smaller intake and exhaust runner volume, on the 302 heads, in most cases, but that's part of what makes them nice on the 351W, they tend to bump compression up a bit, and the smaller runner volume tends to build more low-end torque.

Lots and lots of the aftermarket Windsor heads are drilled for the larger 351W head bolts, and you need to use either sleeves, or shouldered head bolts with them, to put them on a 302.

 

Used 5.8L GT40 upper and lower intake manifolds are rare and priced accordingly. Even the aftermarket solutions are hard to find these days.

Some folks here are adapting a 5L upper to a ported 5.8L but IMHO it is a last ditch effort. Almost worth looking into 5L to 5.8L intake manifold adapter plates unless you have a certified ship date for an aftermarket solution or someone desperate for money selling the 5.8L GT40 intake set.

 

There's a guy locally that has the ecm/harness, heads, upper and lower intake for the 5.8 asking 2k which I'm not sure if its worth it, but I cant rationalize that kind of spending on this project. Not really sure what a set like that should be worth.

 

Could be a reasonable price depending on what they have and the condition, but probably over priced. More information is needed.

Moving to a gt40 style intake is going to send you down a rabbit hole of part hunting and or fabrication.

 

Just like most things, they are worth what somebody will pay for them.