What engine is this?

[Legolas894]

This is a picture of the engine in my 1967 GMC 910 pickup. It has a 4-barrel Quadrajet 4MV (17058213) on it. The block is orange and so are the valve covers.

I can't seem to find an engine code that makes sense. The one stamped on the block near the water pump shows 505506367 (the first digit could be a six). The number cast on the top of the engine behind the carburetor shows 628375 and a K3 under it.

It's a V8 but is it a 283 or what? It's not the engine that came with the truck since the truck's VIN shows a I-6 engine. I took a picture to see if anyone has an idea on where else to look for a number.

The engine is so grimy from years of farmer oil-spray that the numbers I did get took awhile to find!

Thanks in advance!