I see nothing in the VIN that concerns me, just the incorrect fender tag. VIN checks back to a 67 Barracuda with a 273 V8 from factory. Was concerned with a V8 having a 7.25 rear end too, but I guess that was pretty common for an automatic 273 that year.
I also get a 77 Buick tag, but still no explanation as to how and why it's on this car.