5.0 build in 1990 Grand Marquis

[gadget73]

The bottom end is strong enough that the engine block will usually split open before you have problems with the crank and rods. Pistons are fine up to a 150 shot or so as Mercracer indicated.

[Mercracer]

Wouldn't throwing on a carburetor be a lot be alot easier than getting all the necessary parts to to use EFI?

Easier and cheaper.

[Crownvicman289]

You guys need to use the search function over on the corral. 300hp at the crank DOES NOT require any porting and can be done with an HO cam in an Exploder engine with 1.6's. Most Exploder engines with HO cams and bolt ons put out 270+whp with a few creative ones eeking out 300whp. It's not the end all solution, but it's a damn stout street engine.

[Mercracer]

300hp at the crank DOES NOT require any porting and can be done with an HO cam in an Exploder engine with 1.6's. Most Exploder engines with HO cams and bolt ons put out 270+whp with a few creative ones eeking out 300whp.

"Most" is an over-generalization when you do not provide the specifics of "bolt-ons". This is especially true when we are discussing both EFI and carb builds and the relative cost comparison. I can tell you that there are guys on the Corral who are making 300whp with unported E7 heads and a HO cam. Just check out some posts by Ed Curtis. His user name is Ed Curtis. That does not mean that "Most" are doing so (they are not).

You guys need to use the search function over on the corral. .

If you are going to bring up another forum, post a link to the thread (or user name) you are referring to....

[90merc]

Should I use the GT-40 or GT-40p heads. Im not sure of the difference or pros and cons of both.

[johnunit]

P heads flow a bit better, good for 10ish horsepower, but require special headers or creative changes to a spark plug socket.

[zoomie]

specifically frpp , bbk 1515 or stock lincoln logs which are tubular exhuast manifolds off a stock 90 lincoln.
porting works well with gt40 heads,but not so much gt40p, those respond better to bigger valves,and bowl work

[Mercracer]

Should I use the GT-40 or GT-40p heads. Im not sure of the difference or pros and cons of both.

P heads have a smaller combustion chamber than standard GT40 heads. Mustang Cobra heads are the exception. If you are going NA, then the P heads will provide more efficiency and some amount of more power. I believe 10HP is being overly optimistic with a stock HO cam. The advantage to the standard GT40 heads is that you can use any standard header. If you are going to use nitrous or forced induction, I would recommend standard GT40 heads as GT40P heads have a lean burn combustion chamber and are more prone to detonation. Mild porting and surfacing of the heads will easily allow GT40 heads to exceed the performance of P heads.
P heads are more readily available and will typically cost less. GT40P headers are readily available and the same or nearly the same price new as standard headers depending on brand. I use FRPP standard stainless headers and I am using them on standard heads also because I can access all of the spark plugs easily. The "old" FRPP headers were actually more of a pain to work on.

[86VickyLX]

Should I use the GT-40 or GT-40p heads. Im not sure of the difference or pros and cons of both.

P heads have different spark plug angles that sorta limit your selection of headers significantly (without modification that is). Ford 'P' headers are the only ones I'm aware of that can fit with no modifications to spark plug sockets and stuff, they're a couple hundred dollars or so. P heads have been proven to flow better than the GT40 heads, due to their combustion chambers, and make a little more power due to where the spark plug is closer to the center of the combustion chamber, for more a more efficient combustion. They are the best stock factory head that Ford had produced. Which was actually the last head that went on the 302.

[N A]

johnunit is right. Forget the GT40/GT40P heads. You have to go larger.

[86VickyLX]

johnunit is right. Forget the GT40/GT40P heads. You have to go larger.

Not for what he wants to do, he doesn't.

[N A]

I'd like to see how this project turns out.

[85ltd]

I'm still shopping for heads. So, does the mustang come with the GT40 heads stock, and the explorer with GT40p heads?

[Crownvicman289]

Mustang Cobra came with GT40's and IIRC that was a 93-95 thing. The regular GT Mustang got the E7's. GT40's also came on the 96 Exploder. 97+ 5.0 Exploders got the P heads.

[N A]

I'm still shopping for heads..."

Try to find a pair of GT40s in your area. That way you'll avoid paying $100 in shipping and handling from eBay.