GT40 guidance please...

I bought my GT40p heads ready to bolt on (hot tanked, valve job, better springs good to .550 lift, better locks/retainers, and new valve stem seals) for $350. I did spend a little time cleaning up the exhaust roofs and blending that back to the bowls. Do your research if you plan on porting them...some of it makes little difference depending on your combination.

id stay away from the explorer intake, they have tiny ports compared to cobra and real gt40.

you want the gt40 lower to end in "AA" near the dizzy cutout, thats the good lower

iron 40's usually sell for $300 complete but no rockers, get a set of 1.7 cobras they go for about $100-$150 that'll wake up the stock cam a bit

personally i'd look for a set of heads and cobra intake already ported.

you want the lower matched to a felpro 1250, and make sure the heads get a good valve job and at minimum the exhaust ported. if money allows smooth out the intakes on the heads too just in the turns. dont hog out too much you'll lose velocity.

an extrude honed cobra would be a great intake for that combo

basically if the port work is already done you'll get it for about nothing. as the stuff will sell for about the same ported or not.

cobra intakes sell for about $200 and i bought an extrude honed upper and lower for $400 (there was $600 in port work)

that combo would be good for an honest 300 hp and run 12's in a full weight gt.

but thats my opinion

notchback said:

id stay away from the explorer intake, they have tiny ports compared to cobra and real gt40.

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I don't know if that is true or not for the upper, but the lower is exactly the same across all three intakes. However the upper is engineered, power output for these intakes is almost identical across the board.



The Explorer intake seems to have a bad rep. I don't know if it's because it was never offered in the FRPP catalog, or because it came in a truck, but people seem to discriminate against it. It is every bit as capable as the Cobra or tubular GT40 if you look at the numbers. Lots of guys making good numbers with the Explorer intake.

explorer intakes flow the same as the cobra/gt40 and are within a few cfm of the Edelbrock Performer and TrickFlow Street Heat.

well my port guy is who informed me of the different sizes. and all he said is that 1 is good and 1 is not good.

so when i asked tom moss here is his reply... copied from the thread

"The GT40 family of intakes have the part number that ends in "-BA" or "-AA". The AA lowers have a little more runner exit section - good tip for 100% stock classes if you don't want to cheat. The BA is .96"x1.65" and the AA is ~1.00" x 1.80"


so if you tell me that these intakes flow the same on a 300 hp car i will agree. because a stock intake will support 300 hp all day long. if you flow those intakes on a 400hp or more car... you will see a difference... i guarantee you that.

and my '89 went 12.50's @ 109-ish on a 100% stock motor, valve covers never even off the car. boltons and a 75 shot, so yes stock everything will support 300

notchback said:

well my port guy is who informed me of the different sizes. and all he said is that 1 is good and 1 is not good.

so when i asked tom moss here is his reply... copied from the thread

"The GT40 family of intakes have the part number that ends in "-BA" or "-AA". The AA lowers have a little more runner exit section - good tip for 100% stock classes if you don't want to cheat. The BA is .96"x1.65" and the AA is ~1.00" x 1.80"


so if you tell me that these intakes flow the same on a 300 hp car i will agree. because a stock intake will support 300 hp all day long. if you flow those intakes on a 400hp or more car... you will see a difference... i guarantee you that.

and my '89 went 12.50's @ 109-ish on a 100% stock motor, valve covers never even off the car. boltons and a 75 shot, so yes stock everything will support 300

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Not debating the BA vs AA lower intake thing. I've heard similar stuff. Just saying that (from what I've seen) all three upper intakes are basically identical performance-wise.

NikwoaC said:

Not debating the BA vs AA lower intake thing. I've heard similar stuff. Just saying that (from what I've seen) all three upper intakes are basically identical performance-wise.

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i hear ya... but i disagree. i think when performance is more than 100 over stock you will see a diff fo sho.

just like i disagree with peeps who say they did an intake on a 100% stock car and gained 20hp

but thats also my opinion with no data to back it up so maybe im wrong