I'm using a front external-hub D60 from an '88 Dodge (according to BOM #), and was going to slap on some Chevy 8-lug rims to roll it around the driveway.

No go. The hub-hole in the rim is too small to fit over the Dodge hub, even with all the hub bolts removed. It seemed that it ALMOST wanted to slide over, and a flap-wheel on a die-grinder could have opened up the hole enough to fit. But I'd never heard of hub-size differences causing problems for fitting ordinary 8 on 6.5" rims.

Is this a Dodge thing I'm just not familiar with?

this is normal,
if i remember correctly, ford will fit any manufactory (there center hole has the largest diameter) and dodge will fit ford also, but like you said swapping chevy wheels back and forth don't work............
all aftermarket wheels will fit any make also...

Thanks! I was starting to think it was just me...

Since it's not a hub-centric wheel design, I suppose it would be acceptable to open up the center hole to fit over these Dodge hubs. The rims aren't being used for anything else anyway...

If you grind be sure to destroy afterwards. My brother bought a cj
with ground center holes and now can walk only with aluminum cruches. Metal fatigue cracks opened from the lug holes to the center rim which was ground to fit, the rest is history.

Antone