I do #14 head's all the time, have even welded a handful and they've all been fine. While, the best and preferred route is replacement with 17 and up heads, the welded ones have been doing fine (one has logged about 60k miles 5 years problem free, SO FAR lol).
Do absolutely as jt20 said and remove the head and use new head bolts with the updated gasket design if you intend on keeping the #14. You'll be doing yourself the favor as you'll be able to see cracking between valves / valves to prechamber while the head is off far forward of installing the motor. The cracks don't usually happen immediately either, they start to form primarily off the valve seats and work their way deep into the head. Catch it while you can.
See:
W126: OM603 #14 Head-Ache, P.2 | Artisan
For pics of one I'm doing as I type this. This particular head has seen no overheating that the owner or previous owner has experienced, just 250k+ miles of heat cycles. The heads WILL crack, it's a porous cast. The late heads and especially the upside down #22's are absolutely fabulous compared to the #14's.
Reseal as much of the motor as you can. Don't waste time putting it into the car without front/rear mains, timing cover, pan gasket, etc. You've got a chance to do everything easily now, just get it over with. You'll thank yourself later.
Get a low temp tropical thermostat (special order from merc) and a 606 fan/clutch assembly if you have enough space to keep it. Otherwise a pair of 12" SPAL should be perfect.
Good luck.