Fuel pump probs on 88 Silverado

I have a 88 Silverado I'm working on I just pulled out the original 350 with the trottle body injection..I repalced it with an older model carbed 350, I used all the accessories from the original 350 so no probs there..I blocked off the original fuel return and connected the feed line to a fuel pressure regulator and connected it to an Holley carb...the prob is that the engine isn't getting constant gas, when you turn the switch to the ON postion you can hear the fuel pump turn on and see the gas in the filter fill up, when you crank teh engine it starts right up, but when it burns all the fuel out the fuel bowls it cuts off, indicating that the fuel pump isn't feeding fuel...I'm inclined to think it maybe the fuel pump relay but not sure and don't want to wast money on one if its not the prob, anybody have any ideas?

If your using the original fuel pump I think you are going to need some type of return. They make much lower pressure electric pumps that go into the tank.
If you find a small orfice of some type you could run a constant return to the tank and have plenty for the engine. And still use your pressure regulator.
Use a thread connecter and filll with silver solder and drill a small hole through it.

I got it working it ended up being something withthe factory relay installed an aftermarket relay and it solved the problem...

I glad you got it working. The bypass allows the pump to keep cooler. All you need is a tee before your regulator to the return line. They can also get air bound in hot weather without adequate circulation.