How much power to expect replaceing the stock throttle body to a 52mm? Stock heads, and intake mainfold.

1996 Z28...Borla Catback, K&N intake, ceramic elbow, 160 stat, 3.73 gears, hypertech programer.

 

imo, little to none with stock heads and intake.

 

A foil would be best then?

 

As a start: Dump the hypertech on some unsuspecting fool; get a mail order tune and some headers. The income from the hypercrap will help pay for your tune and the savings from buying the TB will get you some headers. The hypertech is worth like nothing in power whereas a mail order tune to lean the A/F can be good for some ponies, even without a cam and heads. The headers can also give you increased power, whereas going to a 52MM on a stock intake and heads will provide neglible gains.
JMHO