At what AFR would a YB engine melt in 4th gear and how long have you got...for example if i saw say 14.0+ for 1 second before letting off is that gonna damage the engine or have i got much more time?..I understand in the first 3 gears you are not under load long enuff to melt.

I am aiming at around 12.0 AFR @ 1.6bar held...is that too rich?