Newb with a 225 needs assistance

Hey everyone, I'm new here, though not new to old cars. I've been around Mopars since birth pretty much. Anyway, I got a 69 Valiant as a first car a few months ago, and I need some help with it. It's always made noise(lifter noise and the clunk going from park to reverse), but now it's making noises that really worry me. It overheated on the express the other day(stuck thermostat), and now it has a number of new noises. The most major noise is a metal on metal grinding noise, which doesn't sound good. It appears to be coming from the general valve area(above the pistons), so I'm hoping it's not serious, but I want someone that actually knows what they're doing to help. The oil light comes on when idling at a light or a stop sign, and I hope that it's just the oil pump. If it helps, all the fluids check out okay. The oil is not white. This car is a daily driver, and I like it, so I'd like to try and fix it. If it is bad, I have another slant, and a 318 poly I could put in it. Thanks for hearing my plea.