I know this is a pet peeve for many. But here in Colorado generally 91 octane is the highest that is available at the pumps. I have a 69 442 with a 455 out of a 70 Toronado GT. When using 91 octane should I use a lead additive and/or some type of octane booster? No nothing?

 

For a weekend cruiser, I wouldn't worry about lead additives. As for octane booster, does the car ping or not?

 

Car is a weekend/show cruiser. It doesn't ping but runs a bit rough when cold.

 

Which has nothing to do with octane or lead, and probably everything to do with choke adjustment.