I've had to repair the usual things to keep a 27-year-old car on the road -- lights, wiring, hoses, an alternator -- and am making plans for some downtime later so I can replace the cylinder head, injector gaskets, and fix the dashboard with a fiberglass repair kit. I admit, I haven't done much at this point other than collect parts. The biggest thing I'm concerned about is having a replacement inner fender welded to fix the hole in the firewall. I'll have to fabricate a new faceplate to fit a different radio, but I can do that with hand tools.
I wasted a lot of time this summer with an old Volvo I was considering putting a Chevy 350 in, but I have no use for a four-door sedan and I think an MG B with a V6 from a Camaro would be a lot more fun.