Wow, that's knocking a lot of timing out of it.
I have had a fair amount of success running high compression engines with cast iron heads on the street with pump gas. But I'll admit, with pump gas getting worse, I felt the need to cheat a bit with mild modification on this build knowing it was going to see a lot of street miles.
So when I built the 302, knowing a steady diet of 91 pump would be used, but not wanting to detune, I took extra precautions. Making sure piston wasn't in the hole (near zero deck height promotes better mixture motion and fights detonation) I also removed all sharp edging from the piston crowns, as well as the combustion chambers. I run a cooler plug, and I also keep engine temps in check with cooler stat. We were also careful with camshaft position, making sure we had enough off seat timing with later intake closing so as not to build cylinder pressure too early in the rpm range.
Really have to stay on top of the tune as well. On the dyno we found 36 degrees to be a happy spot for the engine on 91 octane, where it made best power and no sign of detonation. Carb jetting was 74-72 front side left to right, and 82-80 rear left to right with the rear power valve blocked. Stagger jetting helps the lean cylinders and makes a smidge more power.
Driving the car during the hot desert summer time is where I was most worried. Hot ingested air and warmer engine temps under load is where I thought I might have a problem. Engine never ran over 185 shooting with a temp gun, and plugs are showing no signs of detonation.
I'm willing to bet if I wanted to run some high octane race gas and crank some more timing in it, 38-40 degrees maybe, It might make a few more ponies, but I'm extremely happy with the performance and how the car drives on crap pump gas. When the car hits the track I may play with timing and fuel just to see if I can find anything.