Will fouled spark plugs couse a Chevy 350 not to crank after cleaning the carb?

no The starter should engage whether the plugs are fouled or not. However, the engine may not start if enough plugs are fouled. If you feel that you have flooded the engine or fouled the plugs you may need to clean them before it will start. If you have caused the carburetor float level or other settings to be significantly changed, the engine will flood and it will not start.