TB 70mm vs 75mm?

[citmov]

Anyone running a 70mm or 75 mm TB? I'm about to swap out my intake and wondering what would be better or if there's really a big difference b/t the 70 and 75. Any thoughts?

My set up is pretty stock.
-Intake will be either Cobra or GT Tubular
-E7 heads w/5 angle valve job on the heads & bowl blend v-job into the ports

What do you guys think?

 

[NIKwoaC]

From a performance standpoint, there is practically no such thing as "too much" throttle body. However, I will say that the GT-40 style intakes have a 68-70mm opening on them, so bolting up a 70mm TB would take very little grinding to port match, if any. A 75mm, on the other hand, will require some work with the Dremel tool to match it up.

FWIW, I had a 70mm TB on my car with the stock intake (port matched) and stock heads for years.

 

[Rick 91GT]

since your manifold will only fit a 70mm with out porting id go 70....

 

[Bullitt95]

since your manifold will only fit a 70mm with out porting id go 70....

What he said. I have a 75mm TB and I ported my upper intake to match. Although it's more than I need on my current HCI combo, I've left room to grow if I decide to upgrade the heads/cam later on.

 

[citmov]

Thanks guys! Appreciate all the advice.