12.5:1 Compression Fuel Requirements

[V-DRV]

12.5:1 at 4500 to 5000 ft elevation what octane can you get away with and whats the cheapest way to obtain that octane? Motor will probably rev to 7k and the motor is in a v-drive. Wondering if I could get away with octane booster added to premium or av-gas mixed with premium or if a guy would need to bite the bullet and plan on running c-12 or similiar race fuel. I hope I have given enough info.
Thanks

[IMPATIENT 1]

12.5:1 at 4500 to 5000 ft elevation what octane can you get away with and whats the cheapest way to obtain that octane? Motor will probably rev to 7k and the motor is in a v-drive. Wondering if I could get away with octane booster added to premium or av-gas mixed with premium or if a guy would need to bite the bullet and plan on running c-12 or similiar race fuel. I hope I have given enough info.
Thanks
never use octane booster, it'll eat fuel pressure regulator diaphrams up quik!plus it only turns 93octane into maybe 93.5

[jimsplace]

I would run straight AV gas. I ran the AV with 12.3 at 500 ft. for several years. No problems