stock on my 96 camaro is a 48mm throttle body. the only other ones that i can find are 52mm and 58mm. ecklers camaro says " For radical combinations the 58mm unit is suggested. The 52mm offering is ideally suited for use with mildly modified engines." so what would be the difference. could i still use the 58??

 

'96 so a 3.8 V6, right?
I can't see any reason why NOT to go with the 58, I mean the 52 was stock on my Cav Z24 (2.4 L, why smaller TB on a much bigger motor?) and 52 I think is stock on a Fiero 2.8V6 so the 58 in my Fiero's case would be an upgrade, and a minor one at that.

You *might* lose a little of torque on the bottom end (not much I'm sure) but it will be happier on the high end. Especially with the bigger 6.

 

how would i loose torque? (btw its a z28)
58 isnt going to cause any issues is it?

 

The dual 52 MM Tb on the Z28 is adequate for up to 400HP. Going to a larger one will not add much power because the engine already gets all the air it needs. The larger TB will givequicker part throttle response because with the same amount of pedal travel, the actual throttle opening will be larger; however, at WOT there will be little difference.

 

Z28's a completely different animal, in which case I defer to the above information.

As far as "losing" torque with a bigger throttle body, if you oversize the TB, your low RPM intake air velocity can suffer and cost you a few ft lbs. but your top end will gain it back and then some generally.

But yeah, v8 Throttle bodies are already quite large, so you're just fine running the OEM one as previously posted.