I had to do something similar, I had a hi-perf Chevy water neck that I wanted to use and found a nicely formed hose that fit the radiator so I made a couple of offset aluminum adapter plates and had a friend tig weld them together after I was happy with the orientation.
Nice work but;any Chrome an or polished were gaskit or hose goes is a leak ready to happen,ruff up all gasket an hose contact,so they get a grip. Do it now,don't wate for I told you so.
strange, you could just buy a thermostat housing from a later model Chevy and bolt it on. here's the crappy chrome one, they made them aluminum or iron also. http://www.oreillyauto.com/site/c/detail/MRG0/2661/01397.oap?
I use cast aluminum Chevy water necks I find on eBay. Those Chinese chrome necks rust out in no time. Gary
A good old fashioned corrugated hose would fix that.... http://www.oreillyauto.com/site/c/detail/GATC/25251/N2532.oap? but I like how you got to do some fun design and machining work. That is always a pleasure!