It is the same engine, they are both 2.2's, my Omni and your 600.
Your 85 would have been unintercooled "log" style intake manifold.
My car started as carburated naturally aspirated. It is now turbo with water/air intercooler, FAST fuel system, EDIS-4 ignition and alcohol injection. I also upgraded brakes and went to 5 bolt hubs. I've building it off and on now for a year and a half or better.
I also swapped in forged rods, full skirt pistons ported head/ported exhaust manifold, 2.5" exhaust, an EGT, oil cooler, and an did the entire engine harness (its nearly done, the parts that are done blend in and are hard to notice).
I actually have sort of done this swap twice in some respects. The first turbo setup was the non intercooled log style intake manifold, with a production EFI, it ran 14.8's in that trim at 11psi. This time its all of the above listed with a production tuned manifold (its hard to believe they put an untuned manifold on). The switch from the two intakes required all new everything which is why I may have gone overboard. I hope to be able to run 12's on street tires with the production turbo, it will be a challenge though. But I should be able to do it all afternoon on a road course or a drag strip as I've installed extra coolers/filters that they never came with.
Hopefully it will be a 100% streetable car with no sacrfices besides maybe ride quality, it handles flat insane, its 2500lbs with 205/50/15 rubber, or about 8" of tread on the corners.
Should be done in a month or two.
The Mustang won't get modded until its paid for, but you can imagine what kind of plans I have in mind. Its either go nuts on the Mustang, or go nuts on a Lincoln LS......it'll be a while.
At least its not a Honduh!