I'm not into roller cams myself, but others here can help. Have built a couple of 389's with dished pistons for 9:1 compression and with matched cams and they ran just as hard as 10.5 engines but on 89 octane fuel and no pinging. So, if you are running your #12 heads, you will need dished pistons. With the right cam, you may even gain power, especially if you zero-deck the engine. Lots of information on this website. Good luck.
If your engine is already built and doesn't need new pistons, but just a cleaning up, I would shelve the heads and install aluminum heads (72cc) and be done with it. Cheaper than a total rebuild with new pistons and it will run just fine on pump gas. I've been driving '60's Pontiacs since the '70's, and since about 1990, have yet to see one that ran on pump gas without pinging if it had 10.5 or higher CR. I ended up installing later model 87cc heads on my '67 GTO so I could drive it on 91 and it will still detonate on a 105 degree day pulling a load. You are in Antioch, which is almost as hot and arid as Fresno. So you do not want to run high CR with iron heads on pump gas.
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Jeff 
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