Cant don't forget exactly what the B is, but TDC is Top rated Lifeless CENTRE for for timing. All 20V's, whether in the coast or highveld must have a btdc of 10 deg. Meaning your inventory timing need to be established at ten. The engine's AFR would seem normal at https://travisabzys.dailyhitblog.com/40064917/the-greatest-guide-to-4age-20v