I want to put a throttle body on my '99 SS LS1 but im not sure which size would be best or which brand to choose from. I was considering an 85mm but idk. Also, my car already has a K&N cold air intake. Any advice will be apreciated.

 

From what I've heard, a larger throttle body won't give you much of a gain unless you've done ported intake/heads and a cam. Its kind of like putting a 4 inch exhaust tip on a 3 inch exhaust, if you catch my drift, unless you increase the flow all the way through it won't make much of a difference