So I've seen a bunch of posts about throttle body spacers, and I understand how useless those are. What I want to know about is actually swapping out the throttle body for a larger one. I'm looking at the BBK 65mm Throttle Body for the 4.2L V6 engine. What I'm wondering is what kind of gains I can expect, is it worth the cost, or would I do better to open up the back side with a higher flowing exhaust? I realize that the 4.2L is never going to make the power of a V8, I just want to make it live up to all it's own potential.

 

What are your current mods?

 

Other than a K&N Filter on the intake and a fresh engine, it's all stock.

 

If your still running the stock intake piping I would suggest getting a full intake kit over a bigger TB at this time. i would also do some exhaust work before a bigger TB as well.

Also i have no direct experience with aftermarket or larger TB's on these trucks. But i am familiar with them for the gm 3.8L supercharged engine.
Curious what is the stock size TB inlet on both the v6 and v8 engines?