The EC Inlet Seat Gasket Alignment Tool Kits are the tools to align the copper seat gasket in older Tillotson carburetors. 

By aligning the gasket with the seat gets you a complete seal and no blockages that would hinder flow through the seat. Most newer Tillotson carburetor will self align the gasket so you do not need this tool. 

718 The .125 x 2 dowel pin is for older carburetors that do not self align the copper inlet seat gasket. This tool is used in conjunction with the 36A-38M Inlet Seat.

36A-38M Inlet Seat (Short) Machined. This is not a functioning inlet fuel seat but an inlet seat modified to allow the 718 dowel pin to slide through to align the copper inlet seat gasket. Do not attempt to use this in a running carburetor as the inlet needle will never seat and you will have a terrible flooding condition