I had not previously seen a picture of the lifter galley of the KF 288. I would say the lifter spacing is weird, but that is based on a life time association with SB Chevys. The small, round intake ports are like what would be found on flathead 6s & 8s, and if you ever tore down a Flathead Ford V8, you would know those weren't particularly generous either. We are judging what we see from the past on the basis of what we now know to work.
I am told the engineer came to KF with his prior development history of this V8 and left to AMC with more experience gained from the KF experimental engine. So it seems the AMC 250/287/327 wasn't just the KF design carried over. On the other hand, the short period to production shows it wasn't a blank paper design either.
This 1st AMC V8 compares reasonably with Cadillac, Buick and Olds V8s which required significant changes for 1957 and were completely replaced by new designs in the 1964-66 period.
In the way of other competition, the 1st Ford OHV V8 was a disappointment and should have been called a dud except they made so many. The Y-block Ford had shallow rectangular ports with pairs stacked on top of each other! They gave up on getting any hp out of this engine by 1957 and stubbornly kept making it through 1964 in the trucks.