Short update:
I was convinced the front end on this 1978 292 I have is from a 250. It turns out, the odd harmonic balancer I see on the front of my engine is for a 292. I have tried to upload a couple image of the balancer I have here in the shop on the forum, but I don't seem to be able to. My balancer has a wide space between the first two belt grooves. The alternator and water pump pulley from this engine has the same wide spacing.
I did find a couple of images of the same balancer online though. If any of you can confirm this is a 292 style balancer, I would greatly appreciate it! It's from a 1978 C20 pickup.
Here are some links to the balancer style that I have.:
