[Nitrous Injected]

My brother and i are building a 331 stroker all cast iron block with parts that we can get and fix ourselves....My question is , what year did the GT40 and GT40P heads come on the FORD EXPLORer any help well be great i am heading to the junk yard today to find a set.....331 small block,Ported and polished GT40 upper and lower intake, 180shot of nitrous , 4.30 gears,long tube headers,prodyno tune,70 mm TB,8.8 with 9in end caps, and hopfully soon aset of GT40 or GT40P heads that i well send off to get worked over........all this and more in a .........RANGER?, MUSTANG?, CAMARO!!??? JK,??????? YOU TELL ME WHAT WE SHOUD PUT IT ALL IN.

[95StangMX]

why 331 and not 347?

[Traidmarx]

i'd assume because he said they're piecing it together that they'll be working with an older used block and probably just don't wanna bore it out that much..

[darkhorse50]

1996-1997 (1/4) are GT40 heads, can be identified externally by a series of 3 raised bars on the end of the casting or by the "GT" casting on the right outboard corner. Should have a part number prefix of "F3ZE-6049-AA" or "F4ZE-6049-AA"


1997 (1/4)-2000 are GT40P heads, can be identifed by a "GTP" cast into its right outboard corner, aswell as a series of 4 vertical bars cast into the end of the head. Also the underside of the GTP head is distiguished by the parts number prefix "F77E"

[darkhorse50]

if your trying to build an iron headed stroker, why not try and find some used World SR. heads, on ebay or craigslist

[Nitrous Injected]

ok stupid question , but, what are the World SR heads??? sorry for the lack of knowledge.....i own a 2003 mustang and just now started on the older pushrod v8s

[Nitrous Injected]

yes this is a older block and no i do not want to split it in half so 331 ci is what we are going with.....i was even thinking of going with a 306

[mustang1994bob]

my ported gt40p heads just stomped the crap out of a guy with World SR heads last week, just info love my car

[Nitrous Injected]

what kind of port job did you have done to the heads, and if you can even give me befor and after cfm numbers...if you can that is

[White Thunder]

Originally Posted by Traidmarx i'd assume because he said they're piecing it together that they'll be working with an older used block and probably just don't wanna bore it out that much..

the bore for a 306, 331, and 347 are all .030 over stock

[White Thunder]

if your going to throw all this money to gt-40 heads i would look for some better ones....you can find some nice used heads or a cheap set on aluiminums for under a grand....your going to end up having 600 or so in the gt-40's

[mustang1994bob]

thumper's stage 3 setup, (he has been in the business for a long time, just google thumperoforangepark )with stock sized stainless undercut intake valves and I bumped it up just a bit with cobra sized exhaust. also have some nice high rpm duel valve springs and 5 angle valve job.

stock#s Intake is about 196@.500 and 139@.500 on the exhaust

afr 165's-----------I-243@.500 and E-185@.500
MY GT40P's --------I-230@.500 and E-170@.500
world products sr---I220.1@.500 and E151@.500
just some good info, also have my gt40 intake ported by tmoss

could post pix if there was an interest

[WildWill]

^^^ there's interest... pics please

[95StangMX]

Um newsflash guys the bore for a 331 and a 347 are .30 over making it a 306 with a stock stoke/ crank.........the only difference between the 3 is the stroke you bore them all the same. Only difference is more cubes more power....you are already spending the money for a rotating assembly so might as well go 347 but with either motor gt40 heads are going to be its biggest fail point they are going to hold back either stroker motor..

Edit: just saw that you already said that WT lol...you beat me to it....next they are going to say that the 347's blow oil.....whatever but +1 I would not dump money into porting gt40's unless you have someone that really knows what they are doing and is going to do it dirt cheap/free. I would definately put that money towards good aluminums and would put the money for the rotating assembly towards a 347. It all depends how much are you planning to spend. And if you are wanting to do it all yourself then I would probably just go with a 306. cause its less money at the machine shop just a bore/cleanup and you dont have buy a new rotating assembly, the gt40's will work decent with it....but its your deal

[mustang1994bob]

Ok Will, i'll work on hunting up those pics, may take a day or so cause im in the midle of moving