Bolts missing --> Cracked 904 case
That does sound like a possible explanation on how this happened.
I am definitely leaning toward using locktite on the bolts going into the crank and converter.
I can torque the converter bolts and flexplate to crank bolts no problem, I will have to find the torque specs on those.
As far as the bellhousing bolts to the engine, there is no way I will be able to fit a torque wrench on those, so some new lock washers and bolts will have to do.
Also there were more than a couple other things going on with the car that suggested some inexperienced work had been done to it. I have learned lots from repairing this car so far.
Thanks for the reply Dubob