|
I'd go up to 90. So have on hand at least 80, 85, 90. For fine tuning you can buy the in between sizes of 82, and 88. But the first three ought to cover you for pretty much any condtition. 75 or 72 is probably what's in your stock so don't buy the smaller sizes as you're not going to be keeping a stock exhaust.
But if you truly have a secret 63 engine you need to always put in premium gas. These engines have a tendency to have very high compression and are prone to knocking when using regular fuel.
|