I've just installed a new 350 HO Deluxe into a 67' Camaro. I am having fuel system problems. The mechanical pump won't work, the fuel pump pushrod does not move in & out when the engine is turning. I installed a Holley "red" elect. pump, but it seems to flood the carb. Is this engine intended for a elec. fuel pump, or will the standard GM sb chevy pushrod the wrong size?