If I'm using a the holley TBI/EGR intake manifold (hypothetically, i haven't bought it yet) ... the one with the 2" throttle bores.. and I do ultimate TBI mods to my STOCK TBI unit (with 1-11/16 bores)... I know I need to carve out the bores on the top of the unit... BUT should I carve out the throttle bores on the bottom side also... to make sort of an hourglass shape (in the cross-section),?? would it help with flow ??, would it mess anything up ??
thanks
LONG LIVE THE TBI (actually, that's just what I'm telling myself... becasue I can't afford anything else ..lol)

 

I think you lose velocity on the intake charge if you use a 2" manifold with a 1 11/16" throttle unit on top. My advice is you either use an adapter with 1 11/16" bores or get a Throttle body with the 2" bores and put your stock injectors or injector pod on it. Just my .02. As far as the ultimate mods go, if by carve out you mean the step in which you radius the tops of the bores, only do that on the top.