So I've purchased one of these.
It's a procomp 4150 style throttlebody. Received it today and seems quite well made and should be able to work with it. Very smooth throttle action with the ball bearings on each shaft. I've purchased a cheap $15 TPS from a V8 ford bronco (as it fits and turns in the right direction), and the GM IAC supposedly fits.
Also purchased an NVRAM for a '424 pcm along with an autometer electric speedo and plan to run the electronic auto. I have another VS V8 stato sitting at home currently which I plan to fit all this gear to and get it all working prior to doing any work on the ute. This means that when I fit the new engine I'll be able to start it and run the cam in straight away without any messing around. Pics to follow as it progresses.