[glock35ipsc]

The sending unit for the TBI will have three ports: feed, return, and vent/evap (well, at least running to the charcoal canister). It will also have the pump placed in the tank on the S/U.

The tanks are physically the same, except the 87 tanks will have a bowl that the pump pickup sits in to keep the pump from cavitating. It will still work with older tanks, but at around 1/4 tank of fuel left you might notice that the engine stall or dies when you come to a sudden hard stop or during hard cornering. My 85 ran TBI with the original tanks just fine until I swapped to a 5.3L, than I switched out to 87 tanks.

All you would need to run in-tank pumps are TBI sending units:

Sending unit, 1987, D/S, Dorman #692027, $94.00 ea, rockauto.com
Sending unit, 1987, P/S, Dorman #692044, $101.00 ea, rockauto.com