I had a search for some Lycoming t53 photos over the last couple of days as well as trauling the web for UH-1B photos too. The best thing I did see was info on CD for sale on eBay. The title to search for is "UH-1 Huey Helicopter: 77 manual CD, 8314p/Iroquois Bell" and I think it is the closest you will get to the detailed diagrams and illustrations you are after. Its basically a CD (ebook) for a whole load of huey variants starting at the B version. Prices start at $7.50 if you want to bid, but you can buy it outright for $12+shipping. Not much really for 8314 pages of info!!
Another possible source is a book that is supposed to be an excellent general reference for us gunship builders. It is called "uh-1 huey gunships walkaround" by Wayne Mutza. I havent recieved it yet and am still eagerly waiting its arrival.
Finally, just looking I have found walk around photos for a "D" version (http://www.b-domke.de/AviationImages/Huey.html) I know its not exactly what we are looking for, but the engine closeup was of most interest.
Grandadjohn, maybe you could pitch in here. Could you have a look at this site and give us an idea of how close the T53 engine shown is to the ones used in the B and C versions...if you know? The wiring and pipe detail is of most interest personally.
Hope this all helps!