Hi Dave,
Glad you got going
Re: the hot 429, there are a number of possibilities, including but definitely not limited to the following:
1) need to check for a standard rotation water pump. Turning one backwards reduces flow - there do exist serpentine-belt models meant to rotate the other way.
2) Make sure all the air is out of the system. This is a major one as it took me about six heat/cool/burp cycles to get mine totally purged.
3) There is a flat, thin metal plate that goes behind the pump called the separator plate. A gasket goes on either side of it; one toward the block and one toward the pump. Leave it out and hot, hot, hot!
Others will probably add to the pile...
Tom