I want to do a bigger throttle body on a stock 5.3. What would i gain? And would i have to reprogram? Is it worth it?

 

Think about it. What size is the opening on the manifold?

 

i just have the stock tb ported and polished. you can see gains of 5-15 hp and torque.

 

on the new style intakes the T/B =87mm the intake is 90mm
so you could use a Camaro LS3 90mm T/B, but you will need
to tell the PCM it's on there. HPTuners can adj it in the area scalar
for T/B's. or you mite try the LS3 maf it's set for that size.
more air more fuel more power

 

I got a corvette throttle body on my 4.8

 

What year is the TB? 3 bolt or 4 bolt.

 

Porting the stock one does a great job.