There's no engineering reason you need to replace the in-tank fuel pump with another in-tank. Just get and install an external pump. They are everywhere and are economical. Relatively. Napa has them, Autozone, Rock Auto, etc. I got mine at Napa.
Thing most needed would be for all the fuel lines to be replaced. Then install the external fuel pump. It gets tricky if there's rust in the tank or if the in-tank fuel pump has crumbled (not likely) as the external pump needs to pull fuel out through that old pump. Usually it's just install and go, so that's the good new. Might put a fuel sump before the external pump to capture all the goo and gunk and debris that's likely to be in that old tank.
Of course you'd probably want to drop that tank and scrub it out professionally if you can. Costly but saves lots of trouble down the road. That's the time to change all those rotten fuel hoses on top of the tank too.
Anyway, here's a source of external fuel pumps. Thousand of these are used in race cars all over the world every year...Summit Racing Fuel Pumps
They have generic in-tank pumps too. All you need know is the equivalent car model that uses that engine. That was the hard part when I was spec'ing my external pump...matching up the PSI of fuel needed by the engine with the output of the pump. Turned out it was only hard in my mind. It's pretty straight forward after reading a bit about fuel pumps vs engine size.