im have a 1991 rs tbi 305 does anyone make a supercharger for tbi 305's

I think the small Weiand is you cheapest and easiest choice. You didn't say what type of supercharger you were looking for.

You can use a Powerdyne or similar centripetal blower, a screw type blower like the Weiand 144, or a roots type such as the 6-71. The question I ask is why?

For the amount of the cheapest blower you can get a crate engine without any of the hassles associated with a power adder, and many come with a warranty on a fresh engine putting out at or near the power you could expect from a super charged 305.

Larger Dave

The small Weiand 142 (not 144) is a roots blower as well, not a screw. Just to prevent confusion.