Hi, I'm considering purchasing a clean 65 Skylark convertible that came with the 300 ci motor and the 4 barrel/11:1 Compression ratio option. Question (and apologies if this is a FAQ): Will the 11:1 compression ratio be an issue with regard to modern gasoline and engine knock? Or will I be fine as long as I go with the high octane gas? I'll be running mostly at above average elevation (>4,000 ft amsl), which, if I recall, makes a difference too. The seller, who seems like a straight shooter, says knock/ping has not been an issue for this car, and he's running it at lower elevations (near the coast). Thanks much.