Came across this Craigslist listing near York, PA. Guy has a bunch of rebuildable B18 & B20 engines, plus transmissions with OD's for sale. Prices seem reasonable.

https://york.craigslist.org/pts/d/volvo-core-b20-b18-motors-and-good-m41/7163360796.html

Hi Dave,
You’re surely more hep to those things than I, but are you serious about the prices being reasonable? If so I may have to clean out the basement.

Chris,

I've been buying spares continually since I got my second 1800, back in 2001. Back then things were cheap and I accumulated so much that I finally sat down one day and put everything, including item location and the price I paid, into a database. It's really helpful in finding something I need among the many boxes on my storage shelves. It's also quite useful in assessing the value of my spare parts inventory, which is nov conservatively estimated north of $3k. Occasionally I'll see an item on eBay that I already have for sale and note the price it sells for and then go into my database to update it. That process informs me that the prices for 1800 parts have soared in the past two decades. In light of that, while I've never had to buy an engine or transmission to rebuild, those prices just stuck me as reasonable. But I yield to your expertise on this.

My story is somewhat the same but probably on a much smaller scale. Bought an 1800ES with BW35 back in the early 90’s and then realized how boring the auto box was compared to our previous 144 and 142, both with M40s. So the 1800 sat for about 20 years in my garage. Every time I looked at it I realized how much more work it needed. In 2013 I had to move from GA to TX to work the last few years of my career so I drug the 1800 with me so that I would have something to do in my spare time. (Lived in a rented duplex with a two car garage - landlord took care of the yard and other repairs so I could devote time to the car.) I located another ES parts car in Utah that came with two M41s, a B20E (condition unknown), pedals, cables, and all the other goodies to do a “proper” trans conversion. Then I found another guy that was customizing an 1800E with V-8, rack and pinion, enlarged inner wheel tubs, and on and on. He was really working it over. He started with an 1800E that had 24,000 miles on it and not a SPECK of rust. So I scored a whole bunch of the original parts like radiator, complete wire harness, full gauge set, and all kinds of other new-looking stuff for not much money. Finding those parts was a life saver in terms of being able to repair some hosed up wiring, replacing my leaky radiator, getting a full set of working gauges, etc, etc.
Fast forward to 2019 and I retire and move back to GA. Car is STILL not fully road worthy however I have driven it around the neighborhood a bit just to test the tranny. Any sensible person would not have drug all those spare parts back to GA but since I’m not sure what I may need in the future to keep the car on the road I felt I had to do it - spare rear axle and all! I have stuff boxed up by system (ignition parts, fuel system parts, trim parts... you get the picture. Not nearly as organized as you.
Why is it that we want to own cars that we have to house tons of spare parts to keep them running?!?!?!