Heads: GT40, GT40P, GT40X

[V8BoatBuilder]

I have some questions on heads.... What's the difference between the three heads GT40, GT40P, GT40X?

I know the GT40s and 40Ps were used on Xs... which years?

For building up a 302 engine, what are the pros and cons of each head?

Thanks,
Aaron

 

[james t]

GT-40...... used on 96-97.5 explorers. iron.

GT-40p.....used on 97.5-up explorers. iron. revised combustion chamber, exhaust runners. smaller exhaust valves.

GT-40X......used on nothing stock, aftermarket aluminum head offered by Ford. good heads, but for that kind of money, there are alot better out there.

if you want some good heads to build up for little $$$, i would go with the P's. the regular 40's can be built up almost the same. the aluminum X's are decent, but for that kind of money, i would get AFR's or Canfields.

 

[V8BoatBuilder]

Thanks for the reply.

What's the quickest way to ID Std GT40 heads from P heads? I belive my truck currently has GT40P heads, it was built in sept 97. Just curious. The Ford Racing Crate engine has std GT40 heads. What's involved in building them up - is it worth it?

Do headers interchange between the P and non P heads?

-Aaron

 

[james t]

1- regular GT-40's will have a "GT" stamped on the side, and GT-40p's will have a "GTP" stamped on them. if yours is late 97, i am 98% sure it has P's...

2- FRPP has 4 different 5 liter crate motors....
225hp stocker
270hp GT-40 iron heads with E303 cam
320hp GT-40y aluminum heads with B or E cam
345hp GT-40x aluminum heads with B or E cam
if you are refering to the one with the standard GT-40 heads (same as 96-97.5 xploder), then that would be the 270hp version.

3- i have seen dyno runs from a local shop here were the guy got 50hp out of a set of GT-40p's on an otherwise stock motor. this was obviously doing "the works". 50hp for $600 sounds like its worth it too me.

4- you can run regular headers on P heads, with a little adaptation. i think TMSOKO has done it in a ranger. but, header choice on the X is limited to FRPP or custom made, so you might as well buy what fits without doing any swapping.

 

[blk mk8]

all of those heads are to limited dont waist your time by buy them if you dont have them already just buy a nice head from some aftermarket company.

 

[V8BoatBuilder]

What aftermarket heads do you recommend? What kinds of specs should i be looking for when comparing heads to one another?

What are the downsides to purchasing a short block over a long block? If i buy a short block with only pistons and crankshaft, can i bolt on everything and go or does the block need to have machine work done to it?

In your opinions, would you go the short block route and get aftermarket heads, or get a FRP long block?

Thanks,
Aaron

 

[st5150]

Look at a set of Trick Flow Twisted Wedge or AFR 165 heads. You'll need new push rods and roller rockers to run these heads.

 

[98svt]

ive gotta question for ya...when ford switched to the "p" heads in 98, and the "p" heads are so much better than the regular gt heads, what did ford do to the engine to keep close to the same horse power rating....in theory, shouldnt the hp jumped up more than ford rates it.....what im trying to say is the 97 engine should be rated alot less hp then the 98 which has better heads right?? just wondering really b/c i have my 98 engine on a stand in the garage and im guessing it has the "P" heads b/c its a 98 although i havent looked to see, and i would like to biuld it up and sell it....so i was just wondering how ford put better heads on the 98 engine yet still only rated it at 215 hp or somthing like that....sorry for the long reply.....and thanks for the help...

 

[section525]

I think the 97-97s are rated at 210 while the 98+ are rated at 215. I heard that extra five is from the P heads too. May be just a rumor though...

 

[plrs x45]

there are a lot of good posts in this one. The only thing I disagree with is that GT 40 heads ARE NOT good to modify. GT40 heads ARE good to modify. I believe that if you are on a budget, a good machine or head shop will keep the cost down and you can bolt them right back on. My Mustang ran 10.56 with GT40 irons on it. Good luck.

 

[98svt]

hey 525, was the rest of the 98 motor the same as the 97 .....did they use the same cam and valvetrain....was the ONLY differance the heads.....thanks for the info...

 

[james t]

the only difference is the heads. the p's arent that much better than the regular GT-40's.

 

[FMExplorer]

GT40's are good to modify - but what are you trying to accomplish?

I am working on my '94 GT and will be using the E7Te heads - the "crappy" ones that no one wants. The mustang guy down here has them flowing better than GT40's. In fact, the heads + an intake had his fox body running mid 12's. Not bad for a "bad" head.

The main difference with the GT40X is weight, the GT40P will require a different header than the GT40 because the spark plug is placed slightly differently.

What are your goals? Power? Torque? Speed?

I'm building the stang into a sleeper. With 3.55's, manual tranny, the heads, Holley lower, ported stock upper and a vortech, the car will be running somewhere in the 11's. Of course, that would be with someone that knows how to drive

J