homer - the answer to how many parts you can use depends on the kit.
50 years ago carburetor rebuilding kits produced by the major companies contained parts which would only rebuild one or two carburetors; typically a kit would contain gaskets, fuel valve, accelerator pump, main jet, idle jet, idle mixture screw, return springs, check valves, linkage rods, and clips. There would be no extra parts in the kit. Due to the fact that a kit would only service one or two different carburetors meant that the auto parts stores had to stock an immense inventory of different kits. This condition created a "need"??? for a more universal (and less expensive) kit.
Most of the major companies (as well as all of the cut-rate companies) then started producing a "clean-out" kit which consisted only of gaskets, fuel valve, pump, and clips. This still produced too many different kits for the auto parts stores to inventory.
Then some "wise"??? individual determined that the major cost of each kit was the fuel valve and the accelerator pump. Enter now the "univeral" kit. A database was then prepared (today we would call it a spread-sheet) that listed each combination of fuel valve and accelerator pump; and all of the carburetors these two items would fit. Now all of the various gaskets used in these carburetor would be added to the kit and charge the customer a little more for the unused parts. This resulted in a tremendous decrease in the number of kits, reducing the inventory of the parts houses, and increasing their profit. The customer was then told to compare the original gaskets with those in the kit, and use the proper gaskets (I have never been told how the novice customer is to recognize if an incorrect gasket had been installed previously).
Assuming you have one of these kits with a bunch of extra gaskets, you basically have to determine which of the major gaskets (airhorn and throttle body) is correct for your carburetor. The rest go into either the trash or your "maybe I'll need it sometime" bin of unknown parts. The accelerator pump and fuel valve should be used as well.
Jon.
