I have seen umpteen 89-92 Galants in the boneyard with SOHC 4G63's in them so I don't see why putting in a DOHC turbo or n/a converted block would be an issue.

From all the "research" i've done it appears the SOHC 4g63 uses the same 6bolt crank and big rods as the turbo and n/a eclipses do. I poked around on various engine parts websites and the part #'s for the SOHC and DOHC 6bolt 4G63's are the same when it comes to crank and rods. I however have not ever actually cracked open one of these blocks to do a stare and compare.I'm sure whatever pistons are in there don't have the proper valve reliefs or strength to handle any kind of turbo.

Or long story short, I would guess they atleast use the same casting for the block so the mounts atleast might lineup.

Seems wiring would be your biggest headache.

Of course I assume no responsibility if my half cocked theories prove wrong. But it might be a start.