74 Duster Heater core swap tips

G-g-gravedig!
Sorry to rehash this, but I figured I'd ask since I'm here.

Just replaced my heater core. It was kinda shitty to do, but meh. Forgot to connect the ground until the last minute, and kinda forgot where it bolts to. Does it ground onto the clamp for the two lines coming out of the core? (interior side of the firewall)

Reason I ask is I've been having some weird electrical issues so I'm hunting for a bad ground or short.

It grounds to the fan motor housing screw near the inlet and outlet tubes.