You want to find a Motorcraft 2100 carburetor from a small V-8 or inline six-cylinder for your Buick V-6, 258, or smaller V-8. You want the 1.08-inch venturi size; the venturi size is embossed on the driver side of the carburetor body. Common sizes are 1.08 and 1.21—others are 1.14 and 1.02. Some of the earlier Motorcraft 2100s share jets with Holley carburetors, making tuning easier and less expensive. Having the right size venturis, jets, a good rebuild, and proper tuning will make or break the 2100’s function. Oh, and pesky vacuum leaks—those too. Initial tuning should start at 11⁄2 to 2 turns out on the idle mixture screws.