Air/ fuel tuning

i was thinking to buy these QFT metering blocks that have all screw in ifr and pvrc and etc.

Quick Fuel Billet Carburetor Metering Blocks 34-10QFT

can anyone tell me how to tell if it fits the main body ?
its a quickfuel main body but thats all i know
i read on the quickfuel website to make sure it same setup as current carb, but then after speaking with them they said it fits all 4150.??