get a good mach pump. I have a carter HP pump I bought many years ago. My 302 spins to 7 grand and under some hard street runs it never leans out. I have a 700 CFM DP carb too.
no there is an attachment that goes on the cam gear. The pump is driven off this attachment. If you go to the boine yard and remove a mech pump and timing ocver you will understand. I mena how else if the mechanical pump driven? They are all drivine off the cam, chevy uses a lobe on the cam, ford using a loble that is attached to the front of the cam and it touches the pump arm to drive the pump.