Need advice , 75 360

carburetion and rear gear ratio are very close related in the way that the motor will wind quicker the gear ratio is high and that accommodates a larger carburetor when the gear ratio is lower or taller it takes longer for the engine RPMs to rise and accommodate the larger carburetor for that reason a smaller carb may work better for your setup but vacuum secondary carburetors will compensate somewhat for those conditions allowing you to run a bigger carburetor on a given combination