Chevy 250 with funky valve cover

This is in a 68 C10 I'm taking a look at - appears to be a 250 six but what's the story on the weird valve cover?

 

something to do with emissions, a low buck AIR system?

See if the intake manifold is integral with the head (one piece). It's the later design of the engine, which most guys don't like. I don't remember what year they started using them, but I think it was mid 70s.

 

@squirrel never sleeps! That would be my guess as well.

 

squirrel nailed it! Is there anything he doesn’t know?

 

Squirrel is correct. Emissions engine made towards the end of production, before they replaced the inlines with the V6.
Major change besides the strange valve cover is the integral manifold a la the small falcon inline six of a couple decades earlier.

 

Yep, @squirrel nailed it.
That's a pulse air system. Goofy deal.
https://www.smogtips.com/air.cfm

I'll also point out another interesting (!?!) feature. Look at the fitting between #3 and #4 plugs. That's a vacuum port that goes thru the head's coolant p***age. I'd strongly suggest NOT using that head. They are not something that responds well to striping the add-ons from and don't run that well even when right.
It's up to you if you use the short block, but those were malaise era messes. I don't know what the smog testing is like in WI, but you don't want to have that entered into any bureaucracy database. Better to swap it for a similar year engine if you have to. HEI is '75 or newer. I think those heads were later up thru early 80s.

 

..had one those in a 81 Chevy shortbed, great little motor, trailered many cars/trucks with that pickup.

 

Friend had one in a Square body pickup..ran forever once we figured out the vacuum hose leaks

 

I pulled an identical one from an 81 Chevy and installed in a 77 c10 for a customer several years back