Correct heater hose routing for 1966 w/ SBC

[Rust-O-Matic]

On a 1966 C20 with the factory heater core setup and a late 70's small block, does the 3/4" heater hose go to the water pump and the 5/8" hose to the intake manifold? This is what I've read on several threads about 67-87 trucks, but I can't seem to find any threads about 60-66 trucks specifically.

The previous owner had the hoses hooked up the opposite way, with the smaller one ran to the water pump. Based on what I've read, this seems to be backwards. I wanted to see if any of you guys can verify that before I switch them though.

I'm not sure which hose is inlet and which is outlet, and I can't just look at the fittings to decide which hose to attach where, because the PO had 5/8" nipples attached in both places. I put a 3/4" nipple in the water pump while I had everything apart to paint all the brackets, etc. Now I'm kinda wondering if that is the correct spot for the larger nipple.