OK found the specs of the factory boss 302 cam. 228 duration @.050'', .477 lift and 114 ICL. So you are right that it's not very radical, but still large for 302 cubic inches.
I plugged all the data into my desktop dyno with NO porting whatsoever, canted valves/stock ports-and with small tube headers open exhaust it came out 418 HP at 6500 RPM and 405 ft/lbs at 4500 RPM. With the small tube headers and mufflers options it comes out 393 HP at 6000 RPM, and 391 ft/lbs at 4500 RPM. Even with the ''high performance manifolds and mufflers'' option it comes out with 353 HP at 6000 RPM and 358 ft/lbs at 4500 RPM.
One other thing, for some reason these engines came with dual plane manifolds. With the small tube headers open exhaust option, and a single plane manifold selected it comes out to be 459 HP at 6500 RPM and 423 ft/lbs at 5000 RPM. Add pocket porting, and it comes out to 500 HP even. You don't need a huge cam to make big HP.
So, using the exact same cam ,I put in the 302 chevy specs. Wedge/stock ports and valves-202/160 valves, 11:1 compression small tube headers open exhaust and it show 371 HP at 5500 RPM and 393 ft/lbs at 5000 RPM. Smaller valves, no cant to the valves=less power even with more compression. Now of course I'm using the same cam, I'm not sure what the actual specs are for the chevy 302.