My project
 

First of all I am new to the forum, so forgive the length of this post.

1) My son-in-law pruchased this truck and drove it for 2 weeks and the motor blewup

2) Truck 91 chevy silverado - Motor was swapped from a V6 to a 350 V8 with a carb. Some fly-by-night mechanic totally trashed this truck with the swap, cut the wiring harness. Put a Junk motor in it, just to get is sold. Sooo all that said my son-in-law got taken.

3) Here's the Plan - Rebuilt 350, Holley Carb 650, Holly external (Red) 4psi electric fuel pump, hooker headers, dual exhaust, 5 speed manual trans, correct issues with the harness, new clutch etc.

Finally to the issue, removed the fuel take to plug (not required with the external hollley pump) the return line. Want to remove the old electric internal fuel pump and replace it with a standard fuel pick up/filter.

1) Is it necessary to remove the old fuel pump
2) If so what can I put in it's place
3) Any suggestions are welcome

YES Just as I'm sure you suspect (I'm sure) Your not gonna pick up fuel thro a standing fuel pump.
So yes. Remove the pump, and replace it with a fuel line.