Supposed to be a 258 from an Eagle, sometime ~around~ 1980.
The engine s/n is pitted by rust, it looks like:
?10C26
Which should decode as [unknown year] October (a little iffy but there's no 16th month) 258 / 4/2L 2bbl 26th day of month
It came with a stamped steel valve cover, but the manifolds were off and part of a 3 year mix-n-match pile, so I'm limited in placing the year. It looks like AMC went to plastic valve covers in 1980. Given the readable fragment of the first s/n digit I might have a `78 or `79 (which means the Eagle story is right out), or an early 1980.
Anyone have any further clues? The manifolds are available, but I'm not sure what emissions doo dads went with what years. I've got a set of short and a set of long manifold bolts, so AIR injectors might have been part of the kit. Or one set is from something else.
If it is any help, the lower left side of the block has this cast into it:
3235077 H1