the street master only came in square bore for the small block. also, the entry is really confined so check your throttle blade clearance. i know it'll work with a 625 afb, but i don't know on the holley.
if that holley 550 has 1 9/16" bores then you're golden
the street master is satisfactory for a low compression 318. they're small port runners and tiny little plenum. great throttle response but they're cooked by about 4500rpm. fine and dandy for a cruiser.
that said, a performer will do everything a street master will do, only better and pull to 5500