I just did a cold compression test on my 340 and got the following numbers: Should I be concerned about #8 being so low?

Also, these numbers seem high to me. Will this thing be able to run (and live) on 91?

Intake is off and cam is MP 280/.474 purple shaft.

1: 205
2: 197
3: 200
4: 182
5: 185
6: 182
7: 190
8: 170