Actually, if you mean 8k as in 8,000 feet elevation, 85 will be the proper octane. This motor is designed to run 86 (R+M/2) octane at sea level, and the absolute cylinder pressure at 8,000 feet will be less than at sea level, requiring less octane....can't get any less than 85 up here, and I don't think I'd search to find any. 85 works as advertised. Don't believe me?? Go ahead, support the oil companies.
