The pushed gasket allowed that cyl to vacuum oil from the valley.
When it goes back together.. start at 20 initial and limit the full advance to only allow about 8-10 degrees of timing for about 28-30 total. Then do a cranking compression test to figure out what timing for octane used.
For 91 octane 175 will get by ,180 or so is ragged...190 is less than 25 total and dangerous for parts. That's just my advice.