I hated typing it.
Here's the deal on maint.
Who changes oil on your car today? just curious but related.
I change all my oils and do maintenance and restoration. Last winter I swapped transmission and engine on one of my Scouts (went from auto to manual and 304 to 392), switched to electronic ignition, upgraded to a GM style HO charging system with new shunt to bypass factory dash ammeter, wire wheeled the whole underside and painted it, changed shocks, installed new radiator, added a winch and winch bumper and a few other things.
What's the impact of an unforseen $3k-5k expense to you? (i.e. an expensive annual, a cracked trunnion, etc.)
Yeah, that's fine. 20k is less fine, but I'd write the check. 3-5k is fine
Is the airplane going to sit, or are you going to come up with the funds and fix it, and move on, knowing you won't need to fix "that" again?
Fix it asap, my cost per day for it to sit is so high that I'd keep it moving.
What's the impact of your mechanic advising you that the engine is making metal and advises an overhaul?
I plan to source a spare engine and possible 1-2 cyclinders to keep in my garage along with fuel pumps, alternators and starters, but it may take a year or two to find bargains on these (bargain price, but good NOS or OH condition)
Is the airplane going to sit (for how long?), or are you going to find a healthy 5-digit funding from somewhere, and move along knowing you have a new engine?
I'd keep it moving. It's "better" if it can wait a couple of years or longer to do this, but even if it does it in the first year, I could resolve it and keep moving.
Are you willing/able to learn about an airplane and mechanicals, and be willing to owner-assist on things, or are you expecting your checkbook to solve any and all issues from lightbulb changes to gas and parts/labor?