[Rev]

Is this a bone stock '65? They were made (I think all engines except the 271 Hipo) to use leaded regular at about 90+ octane. The 271 Hipo with 10.5/1 CR may have needed a little more (93?).

The leaded gas prevented exhaust valve intrusion into the head valve seat. Almost anyone who drives these cars much now uses hardened inserts for the valve seats in the heads so as to make them compatible with todays unleaded gas.

For my car, I use only Chevron Supreme 92 octane, but that's for a modified performance engine with about 9.5 CR. I may not even need that.

Rev