Ok to try to provide some clarification. I have a stock LT5 throttle body from Rock Auto it is a GM Stock part on a ZL1. I used an adapter plate from
https://www.solerengineering.com/generalmotors.
Car runs great....still in the process of tuning and I have not had the car on a dyno yet as I am still adding a few things.
Listen to Josh....he knows what he is talking about.