I was wondering how big I should get my throttle body, and plentum ported to. My uncle has a machine shop so I can get it done for free. My current mods are lt4 hot cam kit, slp lt headers, Morroso cai, and a flowmaster exhaust. I wanted to know if I should get them ported to 52mm, or 58mm, and how much of a gain should I see by doing this??

 

If you do 58mm you have to port out the holes in your intake manifold, so keep that in mind. The stock holes are sized for up to a 52mm TB max.

 

I don't think there is enough metal in the stock TB to go any more than 52mm. There are people online that will sell you a 52mm home bore for really low $$$.

Unless you are going to a blower setup, or making more than 500flywheelHP, anything over 52mm probably isn't going to help you. And that saves you the need to to bore out the intake manifold holes.

 

Thanks for the help guys.