I'm looking to build my own intake manifold. I've done the numbers, and everything but I'm getting snagged up on the "easy" stuff: namely, I'm looking to go to a 90mm throttle body with a single venturi, and I have 2.5" piping. So in other words, I need to go from 4 inches to 2.5 inches. I looked on ATP but didn't see any transition pieces like that. I would like to do this as smooth as possible; so that would mean on single transition... Which lead me to this:
Link
Some other throttle bodies I'm thinking of include a 75mm Venturi Sized or a Q45 TB. It really comes down to being able to plumb and run everything, while balancing the effects of the size of the throttle body. So... Suggestions?