Crank end play, destroyed converter, 408 nightmare

when I was still a teen, my friend, Art and I were installing a turbo 350 behind a 327 we had swapped into his Chevy van. We couldn't get the trans bellhousing to seat against the block. Foolishly, we opted to use the bellhousing bolts to draw it in. We drew it in to about 3/8" or 1/2" away, when we heard this ominous metal resonating "sproing", and we suspected that was not kosher. We pulled it back apart, and found a busted front pump on the trans. That's when we learned the hard lesson about engaging the splines AND the dogs with the converter neck.