i have a ford racing intake how big can i go on the throttle body? i was thinking of 70 mm but i was reading only 65 would fit on a stock intake. some one please inform me on what is true if they know

70mm will fit, but the stock intake has a 65mm opening. Anything larger is a waste of $$, unless you plan on upgrading the intake in the future.

A 70mm will definitely fit a stock intake but won't make much difference because like was said above the intake opening isn't as large, and the intake itself just won't flow enough to take advantage of that larger TB.

With that said the TB size you select should reflect what mods you are planning on doing in the future. There's no sense going with a 65mm TB if you are going with a wild combination in the future because you'll wind up buying TB's twice, but if you plan on keeping everything pretty mild then 65 may be the way to go. On the other hand if you're getting a good deal on a 70mm you might want to go in that direction so you'll be set for future mods like heads/intake/cam.

i am just going to make my 91 like a 93 cobra. intake cam heads and a good sounding exhaust. may be like 300 hp or so not going to go nuts yet. have a kid to worry about first.