Most likely going to be rebuilding my '72 inline 6 1500. By summer gas is going to be at least $2.50 a gallon here. Is there anything I can do to make the motor happier with 87 octane? It would be at a loss of performance of course, but at 3mpg I'm gonna go broke real quick. I know there probably isn't much I can do since it doesn't have a removeable head, but...