I could tell when I took the upper plenum off, the intake plenum was full of coolant.

I never was really able to trace the chain of events. Lat this summer I replaced intake gaskets. I thought the problem was fixed but 2 months later
Started having problems again, which I thought could be from me
Not using a torque wrench the first time. So I replaced the intake gaskets again, there wasn't much coolant in the intake this time. (probably due to it going thru the heads now) then a couple of days later thebig event of fogging the town with blown heAd gaskets.
I have 140,000 on the dash. I'll help you any wAy I can, I've gotten pretty familiar with all this......