Yeah, it can be done, but it takes some careful work. You can fit an OEM EFI fuel pump into the stock tank without making another hole, but you’ll need to measure everything right so the pump sits properly at the bottom. Cutting the pickup line and connecting the pump to the existing line works fine as long as all your fittings are tight and you use good quality
fuel hose that can handle the pressure. Just make sure the pump has a good ground and is sealed well so you don’t end up with any leaks or fuel pressure issues later.