my experience comes from my first tuner. he was working on a 700hp supercharged mustang. Heads kept lifting....or persay the coolant was overpressurizing at 500rwhp @4000rpm.

took the heads off after the 2nd time doing it. Reinstalled headgasket with plastigauge installed. found out the area around the threads for the headbolts were being pulled out more than the middle of the block and inbetween the cylinders. the guy took material from the headgasket near the headbolt holes. put it back together. made the power and then some. reliable as a low hp motor from what i heard a year later asking about it. This accomplished the same thing as steping the deck. however, it wouldnt have been needed in a lower hp application. it was done to FIX a problem. I've never seen an oring resolve an issue like that where the motor was actually making good power. 200hp NA KA had more problems with orings than without. same thing with a 450hp KA. stock parts ie, stock HG and bolts, no oringing help power reliably once the switch was made.