It's a brand new 421 Trinity Cub engine the only reason why they're backing out is because of the vibration of the bike I'm running 195 PSI per cylinder timing is advance by +5 I'm running 130 octane it 33 mm carbs pilot jet at 58 Main Jet at 165 19 CC domes With 68.00mm Blaster Pistons and only has 3 hours on it