Probably over the borderline of a stock pump. A basic HP pump will do.
The Carter 2 piece HP pump will be fine. I have it on my 416 with around 450+ HP and I run it down some long straightaways at the track that can starve out with a stock pump. I run 3/8 fuel line and 3/8 pickup/sender unit.
IMHO toss the mech pump. get a Carter electrical pump. by the gas tank, with filter next to it. and rig a oil shut off , with a start up over ride, so you have fuel in the carb before you crank it. why in the back? if the pump or filter leek the fire danger is not at the engine. course you do carry a extinguisher in your car? UH?