So. I screwed up. Lower bracket for rad fan. Set it on rad support,clamped ground to it and tacked it. Ground was touching rad and so was the bracket and i didnt see it. Ground path went through rad and burned a hole in a core tube.
Hindsight is 20/20,eh? Pulled it out and pounded some solder to it. Seems to be holding.
I filled it and ran it for 1/2 hour.
the exhaust is going to be a challenge. Yup.