Drama left at the door.
One thing to check on your particular engine block would be the head bolt holes in relation to deck surface. I have seen on a few engines that GM machined the head bolt holes crooked. I had a similar issue with a factory engine where one side blew (passenger side) and the drivers side looked brand new with ZERO signs of failure anywhere. When installing the heads back on, when I torqued the center two intake side bolts (ARP) they would back off slowly about 1/16 of a turn. I would torque them and then take the wrench off and visually watch the bolt turn counter clockwise. I have NEVER seen that before. I've literally torqued over a million fasteners in my life and have NEVER seen a bolt back off before. After investigating the issue I found that the head bolt holes were not perpendicular to the deck surface. Not all of the holes on that side, just three of them. I ended up elongating the holes in the cylinder head and then using self aligning washers under the bolt head. Problem solved. After that I check all engines for this condition. So far I have found three or four blocks this way. One StageI 4.1, and three 109 blocks. Two were factory NEW short blocks.
Not sure if this is your issue, or just detonation on that side in conjuction with a possible assembly issue. I have good luck with Cometics on a 109 block, as I do with 9441's too. The 9441 is a nice safety valve for those not up to speed on tuning.
To check the bolt holes, thread a stud in and use a machinists square along side the stud in 90* incrementals. Only takes a couple of minutes. To fix it correctly takes a good machinist and a good mill work with a step stud or enlarge to 1/2". Thread inserts will work, too.