I can't remember what we started with, but early on we went down to the current 47mm. (Operating from memory) Still a bit oversized on Herbert's 2.7l, but quite usable. More noticeable on a stock 2.5l. Just causes you to reach WOT early. Herbert likes his, but he has two speeds: Idle & WOTMASSIVE PINZ wrote: This throttle body size worked very well in my truck and Herber's Pickle uses the same one and I think Alan will agree that it drives exceptionally well..
In any case, better to start slightly large and work down than the opposite. I imagine your high revver beetles really like the airflow!
Alan