Thanks for the feedback, guys.
I love to salvage good old things but I think it's kind of questionable to rebuild a 40+ y.o. 1st generation stern-drive.
Shop owner kind of concurred and suggested that for about $3000 we bring the drive into the new millennium with a new or recent Alpha 1. I was thinking I could find a lightly used Alpha for 800 bucks and then I brought up the SEI idea. Much to my surprise he down-talked the idea even though he's a dealer for them. He said if it were a smaller 4 cylinder type runabout SEI would be fine but because this was a bigger heavier boat it might be problematic.
I've read only one "valid" complaint against SEI drives and the guy said it on a heavy deep-vee boat with a single 250. If an oem drive of the same gearing has lasted 40+ years on this rig, how much damage can this hull really do to a modern "equivalent" drive. Was that first Merc really that good? Or just properly cared for?
old fielder - this is the only Moesly 21 I know of out here, although it wouldn't surprise me to find some others as there are a lot of transplant boaters out west. I'm only aware of 4 in FL and 1 in HI. I found this one on the west end of Lake Erie Last fall and had a guy tow it out.
