[turbofish38]

Can anybody riddle me this? In my GM 44w parts catalog it says the CHRA for all 79-83 carb turbos(Regal,Century,LeSabre,Riviera,MC) is part number 25516899. Holley has a diferent number listed for each application. Does anybody know what the difference is? Or is the GM part, remanufactured by Garrett-AirResearch, just a generic replacement with maybe looser tolerances in the diameter of the wheels. For example if the largest compressor wheel was say 32mm and the smallest was 31 or 31.5mm than you could put the smaller wheel in the larger wheel housing and maybe not notice a difference. They did the same thing on the hot air Riviera I think and its always been an on going debate because the info was supplied by John Craig. On my Rivs there always seems to be a performance gain when I replace an original turbo with a rebuilt GM unit. John says the Rivs use a smaller comp wheel than a Regal but the parts book says otherwise. Maybe the same applies here?