So my 85 Delta with the 307 "Y" motor is really confusing the hell out of me here.

I replaced the heater hoses a while back and instead of taking the in hose (water pump to the core) and looping it around under the air cleaner I put it in straight, and the other hose ( out of the core into the control valve) but ever since I did that, there has been leaking from the core area.

Could it be as simple as I have to loop the "in" hose in order to make the heater core work again?

 

If you didn't swap the hoses, I'd check to make sure:
1. You didn't crack the "nipples" on the heater core (easy to do...ask me how I know!)
2. The hoses are seated all the way up and the clamps are on straight and above the flare.

C.J.