FWIW, the 512 RB I had used Indy EZ1 heads and their single-plane (which is too tall for a flat-hood Duster).
It had a junk Demon 850 on it which we couldn't clean up, so I swapped my spare 750DP race carb on.
It had really good throttle response, surprising to me with the single-plane & big ports, but 512" seems to "cover" that.
I pulled the 3.91s and swapped to 3.23s, barely noticed except on the highway.
Comp hyd roller, not big but don't recall specs; kinda noisy but no problems.
FBO distributor, F150 epoxy coil, TTI headers, full exhaust with X-pipe.
3500 stall, 275/60 tire. Basically a street car with a big motor.
Ran 11.30s like falling out of a tree.