I don't think any aftermarket pumps just drop in. You have to re-use the canister, wire them up and install the fuel line. I bet you could just install a hotwire fuel pump wiring kit, change the filter and go with 42.5 injectors and not run out of fuel with a ton of more mods and 93.
So you have to drop the tank? I had a safari van like that years ago. What a pain to swap the pump!
I vote you cut an access panel.