Oh yeah, lookit that. First time I've attached pics directly in here; figured you'd be able to click to embiggen, but looks like not. I can host 'em locally and point to them, if you care.
Also, it is possible that the truck 318 head had a different part number?
Yep, it does, that was the point of my posting the FPC pages. The heads I pulled off my '89 during a reseal and refresh of the original engine had casting numbers corresponding to the part numbers in the '89 truck FPC, and they had wide-open chambers.