Well, I managed to get the engine in for a test-fit, and it confirmed one thing- I have a lot of work to do.
To mount it so that the trans tail is in the original location, the A/C module had to come out. I'd planned to delete the A/C anyway, but now I need to fab some kind of heater setup (the G-body heater box won't work either, unless it's modified). This is Canada, you know.... it will need a defroster at the very least.
The headers are good news/bad news. Drivers side fits, period. No mods required. Passenger side, not so much. It looks like one tube will need to modified, possibly even cut out and rerouted. More on this as I figure it out, once the engine location is finalized.
These pics were taken before I realized I'd put the trans mount bolt in the wrong hole in the Energy Suspension trans mount, which has 3 holes. The mount was shifted to the passenger side about an inch.... by the time I discovered this I was ready to call it a night. Hopefully correcting this will make the header fit a little better.