I hear everyone talk about running a 75mm tb if your going to go blown and sometimes when doin heads and cams. What is the proper application for a 70mm tb? When would it be wrong to run a 75mm tb? What are the negative aspects of running a 75mm on a nearly stock vehicle?
The best info can be found over at that 'other' website, m0dulardep0t.com (replace the zeros with the letter O since there is some sort of childish feud going on that prohibits the use of links to MD from here )
Anyway, they did some great testing, including baselines with OEM elbows and both 70 and 75 MM TBs. Dyno graphs included. Click the link at the top of the webpage "Articles" and scroll down the list, looking for The 2V Plenum Showdown (70mm) and The Plenum Showdown Part II (75mm). Written by Ken Bjonnes .