We live and cruise on a 41 year old Bertram. Still 32Vdc and 12V71TIs. Tied next door, 30 year old 12V71TAs. I believe in stocking spares. If I don't have it, tomorrow morning I will for either boat. Probably the hardest to find items on your engines is the exhaust manifolds. Shop, get them and pickle them. IMO, al else is still serviceable. You did comment also short on old Detroit techs your way. I do understand that and this must be considered. If your like me, Your hands have already been into it, we just need some young strong backs.