Not sure what you mean by a "1 line" Corvette fuel pump. Most in-tank pumps only have 1 outlet unless it was designed to be part of a module/canister that had a venturi pump integrated into the bottom of the canister.
(Venturi pumps are designed to use a small jet of fuel output by the main fuel pump via a secondary port to scavenge fuel from the bottom of the tank to fill the canister, so in-tank baffling could be deleted.)If you are doing a 3800 swap, you are always going to need some kind of fuel pressure regulator and that is going to need a return line to the tank, unless you find a regulator that mounts inside the tank and dumps relief pressure directly back into the tank. Note that any such in-tank regulator would probably be a fixed type, not one that references vacuum or boost.
All 3800 Series 2 PCMs are factory programmed to assume a vacuum/boost referenced fuel pressure regulator is being used. Series 3 engines had returnless fuel rails and thus used a fixed fuel pressure regulator. If you want to use a fixed fuel pressure regulator with a Series 2 PCM, some custom tuning work may be required to get it to work correctly with a fixed fuel pressure system.
Modern GM vehicles have done away with the conventional fuel pressure regulator and replaced it with an active fuel pressure control system (usually consisting of a fuel pump control module and feedback pressure sensors). None of this hardware will work correctly with a 3800 PCM because 3800 PCMs are not designed to communicate with FPCM's.
NOTE: most "Corvette" fuel pumps I've seen (like the ever-popular EP-376) are not rated to supply the high volume of fuel flow the 3800 SC engine demands at the 60+ psi of fuel pressure the 3800 SC engine usually runs at with full boost. Whenever you do a 3800 SC swap, you need to make sure you are using a fuel pump capable of supplying the engine with the volume of flow of fuel it needs at the elevated fuel pressure levels unique to boosted engines. The EP-376 pump is not rated for this and, depending on the manufacturer, could be woefully inadequate for the task of supplying enough fuel to a 3800 SC swapped Fiero. I used to recommend the EP-381 pump for stock or very lightly modded 3800 SC Fiero swaps, but it has come to my attention that some aftermarket manufacturers of these aren't making a quality pump and it too may be inadequate for the task. A true safe bet is to only use an aftermarket performance pump - like one of the many 255 LPH units available from quality manufacturers in your 3800 SC swap.------------------
More is more. Less is not enough. Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com[This message has been edited by Darth Fiero (edited 03-30-2019).]