No problems, Id say just as good as whats out there today.. I can dig up My receipt, but I purchased my set in the spring of "03" from Muscle motors... Hardly no port work, ran them like this for a few seasons, then sent them off to Modern Cylinder head for his Winter CNC port special.
Ran them this way for several years, until the fall of "09".
Only problem I had was a leak out of one of the header bolt holes, that were suppose to be blind.. Just thew on some sealant and a stud and that was fixed..
Went 146 MPH in the 8th mile in a heavy Dragster... Around 2300 lbs with driver. Mid 7's in the 1/4... People will say yea, its a pipe rack.. I dont care what its in one second flat 60ft and near a buck fifty in anything is damn fast regardless.