Bill, thanks for the link but I already have the link to the same book here:
http://chevy.oldcarmanualproject.com/trans/4655hmt/index.html The donor parts came from a 1956 Chevrolet truck.
At first I was worried that a 3.38 versus 3.90 rear axle would mean the transmission would shift at wrong speeds and the results would be poor. Not so. Cadillac has the same transmission gear ratio as the truck and there is a 3.36 rear axle ratio example, so the combination is good. That's the only reason for mentioning Cadillac.
The transmission does not downshift at all. So that's why I'm thinking the throttle linkage setting is way off. Not even close to approaching the detent. The owner has other issues to deal with so communication with him is sporadic.
