low power when hot?

Here's the not so short story:
I got this car from my great grandad when I was in high school (so i'm the 2nd owner which is fun) and I loved cars but was clueless on engines and I got completely taken for a ride on a "rebuild" from a mechanic and if I didn't see it in pieces, I would never believe that anything was done besides some cobalt blue spray paint. So the thing shortly thereafter bit the dust and I parked it, went to college and on the side I was teaching myself about cars by doing basics on my daily driver as well as watching and reading everything I could get my hands on about old mopars. I graduated in May and came back with a vengeance to get my car back on the road. turns out the bolts on the rocker shaft had backed themselves out (one of them completely out) so I checked over all the rods, got the rocker put back on and torqued, and checked the timing gears, rotor, cap, points, put new plugs in (although now that they've lived through a lot of test starts and tuning, I might should grab another set) set the valve lash cold (Intake .011/ Exhaust .021) and "bench set" the carb to get it running, then made some idle adjustments from there to get it ballparked. So since then its been sounding good, starts instantly hot or cold, and I've taken it for a quick spin a few times and when its cold, it actually feels decently peppy but i wouldn't be surprised if there were some serious underlying issues that come up and opted for the roadside service and tow on my insurance. I haven't looked at timing since I don't have a timing light (nor did I see a mark on the balancer then I re-installed it) but I probably should figure that one out. Also, I was told at some point it was bored 30 thou over but I have no way of verifying that.

The carb is a holley 1920 reman unit, but I do have the original and a rebuild kit (sans float since those seem to be hard to get)

Side note: what do you recommend for gas because I've seen some conflicting answers. right now it has a fresh tank of regular 87 in it.

I know that's a lot to sift through, and my car has a long way to go but thanks for all the input so far.
Post some close up pic's of the old plugs when you change them.
Still dont know much about your engine?
Depending on the compression ratio 87 octane may be OK, but NO ethanol.