I put a 350 in a 88 chevy camaro needs some help?

to make it short i replaced the 6 cylinder fuel injected with a carbed v8 and now im running in to fuel problems...i cut the fuel pump wires then hooked up the line to the Mechanical pump works fine tell i get down the road then stalls..my guess is it cant pull thru the pump fast enough..so i was wondering what parts well i need..maybe a new gas tank and sending unit?i really dont wanna hook the wires up and run it with a regulator...thanks