DougBlevins

i put a 70mm TB on my 5.0 and was wondering if that's too big. my car has 1 5/8 equal length shorties and an H-pipe so i figured 70mm would b ok, what do all ya'll think, or hopefully know.

91GT5.0

Like I said in the other post, you would benefit more from a 65mm on a pretty much stock car than you would a 70mm. My friend has a 306 w/ f-cam, Powerheads, RPM intake, 76mm MAF, 24lbs-ers, full exhaust, and 3.73's. His car got considerably faster when he switched from a 70 to a 65

kornfan_88

Can I just bolt on a 65mm throttle body without doing anything else? I know I have to do the egr spacer, right?

91GT5.0

You can bolt it on, you do have to get a bigger spacer, or bore out your stock one. You don't *have to*, but anything you feel on a stock car, which won't be all that much, will be even less w/o a matching spacer.

spike306

don't forget that by putting that on, your forcing more air into the stock heads. it will be more afective with some good heads on there

mustang50

depends on your setup. I have a 75mm throttle body.

89muscle

gop with the 65 mm because the airflow will be much faster.

stalker92

I have a 70 mm throttle body with a trick flow inathke manifold, with bbk equal lenth headers, o/r h-pipe will the 70 mm hurt the car? would a 65 be even better? Im also thinking about the future when i get a bigger motor and things like that.

Sean

I would go with a 65, unless you are going with some sort of forced induction.I have a 65 on my track heat with 76mm C&L,it runs great!

roush97

What's the stock size on a "91 5.0 GT?