Speedway Motors has some new carb adapters for Stromberg 97 3-bolt carburetors. They fit both stock intakes and the Offenhauser multi-carb intakes. Best of all, they orient the carbs so that connecting the linkage is easy (rearward pull throttle arms).

The GM 63-75 L6 2-Bolt Big Pattern to Stromberg 3-Bolt Adapter (2-15/16" bolt spacing) works with 1963-up factory intakes, as well as the Offenhasuer 5415 , Offenhauser 5415 , Offenhauser 1409 , and Offenhauser 1035 intake manifolds.

The GM 36-62 L6 2-Bolt Small Pattern to Stromberg 3-Bolt Adapter (2-9/16" bolt spacing) works with 1962-older factory intakes, as well as the Offenhauser 1034 and Offenhauser 1177 intake manifolds.