so anyone have experience with the 320/533 hyd

YR,I believe the 320 cam was designed with low lift for a reason, like stock rockers? But it has more duration at .050 than the cam you discribe, by a whopping 17 degrees, and a 104 lsa that creates a TON more overlap, like 19 degrees? It would definately NOT be very streetable in a small block.
A friend runs a Herb McCandless 268 @ .050 hydraulic with only .540 lift, and i used that same grind way back in 1997. My buddy used stock rockers and pushrods. His Roadrunner clocked an 11.47 running a 451 b motor all corked up at 3800 race weight.
My 475 cube motor pushed a 3200 lb car to 10.10 at 131 with that cam, and was strangled by a 750 carb. The 320 /533 lift cam has 4 more degrees duration at .050 than the HM cam, and a lot more overlap.
My guess is Herb might have had something to do with designing that cam.