The GT-40 tubular intake was designed for a 65mm throttle body. I have read that they can be "ported" to accept a 70mm throttle body.

I have seen no references to fitting a 75mm throttle body -- my question is, can it be opened up that far? Or is my only option to stick with a 70mm throttle body?

I want to keep the intake for 3 reasons: (1) I already own it; (2) I like the asthetic look of it; and (3) I want to keep as many visible mods as possible period correct, as to what an original owner would have done.

The intake will be on a 347 stroker engine with stage 2 ported Trick Flow Twisted Wedge Heads.

Thanks in advance for your answers.

 

Im no expert, but I think with that intake, a 70mm throttle body will be sufficient. With a 347, and those heads, you leaving a lot of potential HP out with that intake setup, just my 2 cents.

 

I saw an article that said the GT40 flowed, and had as good or better torque than the competition intakes ut to and a bit over 6000 rpms. Since I am not planning on winding a 347 stroker much higher than that anyway, I figure I am good with this intake...

I will leave the 7500 rpm excursions to my 69 BOSS 302 at Willow Springs...

The question is still unanswered: Has anyone put a 75mm throttle body on a GT 40 tubular intake????

 

i say no. you "might" be able to for 1/8th inch or so, but your going to be cutting in where the flange and tube welded together. which could cause them to split apart.

a 70 is fine on that.