Fuel system questions, going from EFI to Carb...

Its not worth the trouble.You will need new lines any how.I tried to use my 255lph FI pump with a Holley regulator with 1/2" feed and 3/8" return lines. The pressure would creep slow up to about 9psi then would just sky-rocket past 15psi and I would have to turn the pump off.The fuel system in the car now is a 12 gallon fuel cell w/ a sump,Holley black pump,Mallory reg. #650-4309,and -08AN (1/2") feed and -06AN (3/8").If you have to use the pump,the only way to do it is to drill a hole in the top of the take or the filler tube and run a return line there.You need to do this because the return line that comes out of the pump is to small (5/16" out of the pump,to a 3/8" return line)and wouldnt let the fuel flow freely into the tank.If you need more help PM me.