I'm attempting to fab up my own TBI hat. Space limitations are ,of course, a major consideration. Looking at all of the different TBI hats on GM cars and trucks, I wonder what the ideal shape would be with regards to airflow direction. Some move the air in a swirl to the bores, like late 90's Cadillacs;others send the air straight to the top,like the truck TBIand Caprice. Shifty, JPrevost, Dimented- any opinions? Anybody ever addressed this question?

I would think something like this would be good. It would be relatively easy to fabricate. Basically, just have it level with the tbi base, open on the sides around the tbi, and give the inlet a smooth radius so the air spreads out some and slows down. Obviously the dimensions would be limited to what space is available but Id avoid making the walls of the hat be right next to the bores. Thatll force most of the air to squeeze past the injector pod.

That's what I had in mind. Looking at CFM Tech's design made me think about minimal diameter around the pod, shoving the air in with more velocity, but the GM engineers have a lot more edumucation than i do and I assume they use more technical data than I have available. I already mocked one up but it's not symetrical and I don't have any welding tools to try it out. I'm going to try to find some type of plastic to heat ,bend and mold.