Heater and rad hose pictures?

[big_rig]

I pulled the engine out of my 64 c10 last week for a total overhaul and am finding some odd surprises from the previous owner. The engine is a 292 inline 6 and there is a hose T cut into the heater hose and run to the back drivers side of the block across the bell housing. Anybody have any idea what it could be for? It enters the block right near the back edge via a pipe nipple screwed into the block about centered on cylinder 6 (pic). Possibly a circulating heater may have been in the line before? If anybody has pictures of their heater hoses on a 292 and maybe one like I described I would sure appreciate.