I am wondering how come the biggest throttle body I can find for the LT1 is 58mm. But my buddy for his little 4 banger can get a 70mm throttle body? Is a 58mm TB big enough? will putting one inplace of the stock 48mm TB give me a a lot more power gain?

 

absolutely not. its a good thought, but it won't do much for you until you're pushing quite a bit more horsepower. i don't even have one on my stroker(might be the next mod though)

 

accually u can not put a 58 mm tb on your intake unless its been ported to accept it. u can go to a 52 mm without mods. doesnt do anything unless u do a few other things. im sure if u switched to 1.6 roller rockers and went with 30lb injectors with a 52mm tb, follow these with a tune from pcmforless u would like it. this is assuming u have allready added a cai and good flowing exhaust.

 

i think you would actually be surprised at the lack of extra power you get from a throttle body. plenty of LT1s in the 9's running a stock throttle body

 

Soo true. I would stick with stock till you start needing massive amounts of air showed through it..

Btw: Your tb is a dual tb if I am not mistaken. SOOO 48x2 kind of lol

 

This is how it works...you are gonna have limiting factors when you are trying to make more horsepower. What the guys are saying is that air is vital for combustion, the more air the better (that is why NO2). The 58mm tb isnt gonna help much if you have stock manifolds and stock intake etc. Those become the barriers to making power. If you do buy it just take the gasket that they give you and hold it up to the bolt holes on the intake, then draw on the metal to the inside of the gasket. Then borrow a die grinder and do a "gasket match" that way you will not have the intake as a restriction just the intake runners, intake manifold gaskets, head intake runners, displacement, exhaust manifold, exhaust piping, blah blah blahblah...... General rule...larger throttle body=less throttle response, vice versa.