The original stock tbi pump in a chevy truck with 5.7 engine was the ac/delco ep386. It was always considered marginal and was frequently replaced with either the ep 241 or ep381 which were later used on the tpi equipped engines. As Babywag stated, the psi of a pump isn't relevant since the pressure regulator will bleed any excess pressure back to the tank.
I put an in tank pump together for my step side a few years ago but haven't installed it yet. Because the 1980 j trucks mount the sender in the front of the tank, the pump could become fuel starved at relatively small angles as the fuel in the tank moves towards the rear. Considering that the stock fuel pickup is also largely oriented towards the front with only the fuel sock located further towards the center, maybe it doesn't matter. I have heard it mentioned on this site that if the fuel sock comes off or rusts through that you have less usable fuel in the tank, but that has never made much sense to me since the sock will simply suck air if it is not covered in fuel. Not a big deal with a carb that has a fuel bowl, but it would be a big deal for a tbi that needs a constant fuel flow.
* 1981 stepside, 360, 727, 208, almost stock daily driver.
* 1982 Laredo j-10, 360, 727, in rough shape and in the process of being rebuilt with 401, NV4500, Klune,
. NP205,d60 front, d70 rear, fender work and minimal lift. It will probably take 10 years
* 1973 jcab mounted on 1983 j20 frame. 360/t18/208 d44/d60. Almost completed