Are you looking for info on replacing a current in tank electric pump for fuel injection or are you wanting a electric pump for a carb set up? We really need more clarification on what you are trying to accomplish here.
Ok i have a 1980 caprice 4 door i am in the process of installing 350 crate motor from gm performance but it has no provision for a mechanical pump so i was looking for anyone who had done the same thing but found nothing so i will post pics when I get finished and do a small write up.
Ok what you will need is a small frame mounted fuel pump kit with regulator. You will need to place the pump as close to the tank as possible and below the level of the pickup in the tank. Since it is for a carb then you only need a low pressure pump. Most carbs need 5psi of fuel pressure or less, more than this and you can overpower the floats in your carb and cause flooding issues. It is strange that you say your engine doesn't have this feature. I would make sure it is not there before you proceed, they come from the factory with a block off plate bolted over the mount for the pump. I would double check becuase if yours doesn't have this you might have the wrong engine for your car which will cause more problems down the road with assembly and running. I have installed probably 30-40 of these engines and the only ones that do not have it that I have seen are the engines made for fuel injection and they very a lot from the gen1 small blocks with different cranks, heads, and intake bolt patterns. Just google frame mounted fuel pump and you will see lots of info on how to do what you want.
I just replaced the electric fuel pump in my El Camino. It's got a 90's+ era(?) 350 with no mechanical fuel pump provision, also. The boss is there on the block, but the block isn't machined all the way through for it. Getting it below the tank level isn't crucial but it would help, my Elco sits higher and it needs to prime if it sits for a little while. I put a K&N 81-0402 in it just this past weekend and so far no issues. You'll also need to run a wire from a keyed 12V source. And some fuel line + hose clamps to connect the existing lines to the pump. It has a dual exhaust so the pump is installed where the single muffler would normally sit in front of the fuel tank.
Just make sure you start it and let it run to "clear out" the pump every month or so. I let mine sit for a year+ and the old pump got varnished up and wouldn't work any more.
Ok so i installed a fuel pump under the back seat on the passenger side frame rail there was barely enough room but i took about a foot out of the metal fuel line and wired in a fuse and relay with a filter where the mechanical pump used to be. Will post pics tomorrow thanks for the input everyone