I have the same supercharger unit as above, Paxton SN2000. I bought it off ebay for 850 bucks I think. Previous owner had thrown a rebuild kit at it and it came with the upgraded impellor(a near $200 upgrade). The tech specs on these things seem to be a closely guarded secret, but after enough hunting I did finally manage to dig up all the info on them. Now I'm just trying to figure out if it's going to flow enough to build any boost on a decent 440 combo w/ aftermarket heads, but everything I read seems to indicate these things are right at home on a small block where a big block is pushing them to the limit.