Thanks for all the tips, I really do appreciate it.
I need to get the 140 block to a machine shop for evaluation now. Finding a good one may take a while.
My plan:
-Use the 140 crank case assembly. Inspect and measure bores and have them bored out as appropriate. New pistons and rings of the correct oversize.
-Use the crank, rods and bearings from the 90, including the top bearing assembly and bottom retainer. New seals obviously.
-Use the intake and bypass covers from the 90 to permit re-use of the later recirc system (how does that actually work, and what was it designed to do - lower emissions? improved fuel economy?). The bypass covers appear to be the same shape and size internally.
-Use the ignition system and wiring from the 90 (think I lost a power pack due to heat after hours of trolling during the last run last season, so maybe new ones).
-Try fitting the priming injector system and remove the choke plates.
BTW, the last thing I want to do on this project is 'half arse' the internals. Any savings will be on the 'bow-ton' bits that are easily changed should they prove to be problems. I DO NOT want to go inside the crank case again, not that I'm not having a blast working on this thing.
And not that I'm trying to squeeze the last bit of power out of this thing, but I notice a lot of rough edges in the intake ports. Is there any point in knocking them smooth while it's in pieces?