See posts on the board about LH2.2 upgrade. If your 2.0/2.1 harness (an 83 should be 2.0--there is a debate about whether 2.1 is really a version of LH or not) is intact, you can repin your AMM plug on the existing harness and use the ECU and AMM from the 85 as a bolt in, no relay or other changes. If you are more ambitious, and your 85 harness is the better, you can swap the whole thing in. Lotta wiring, but not difficult wiring for someone who did that other swap!

I'm surprised no one has chimed in about the differences between the B23 and B230. The 85 engine will be a skinny rod motor. B23s are a wonderful base to build a hopped-up motor on, so many people like to start with them (I know I do). That said, I've seen plenty of 85-87 motors run up into the 400k mile range. I don't think they are considerably less durable in day to day use than the a B23. Not an engine to get 300 horse out of though. I try to save B23s whenever possible. I would seriously consider popping the head and having it rebuilt (couple hundred dollars). Even if it was overheated, chances are the bottom end is fine--they are pretty bullet proof. If you think it's toast, bearings can be changed and even honing can be done with the block in place. You've got a wonderful engine hoist. As long as you are considering pulling and such, I'd consider rebuilding that B23. Then you have most of a new car!

DS