bike carbs

[snapper]

I have GSXR 750 carbs on a 2.1 Pinto the throttle response is certainly NOT slow.
The good thing about bike carbs are that they have a variable venturi which reacts to the demands of the engine, better than Webers and so much easier to set up.
A general rule of thumb is to pick carbs with a rear outlet inner diameter the same size as the inlet port on the head, that said 36 to 42mm are ok as the Venturi will raise the needle as much (or little) as the engine requires.

Andy Bates ( he of AB Performance and Dragons Den fame) recomended roller barrel carbs as there is no restriction or throttle plate pivot in the way at WOT, he did say however that the throttle had to be "fed in" and not slammed open.