Cant try to remember just what the B is, but TDC is Leading Lifeless CENTRE for for timing. All 20V's, regardless of whether for the coast or highveld must have a btdc of 10 deg. Meaning your stock timing need to be established at ten. Thats a good idea but https://toyota-4a-ge83703.dreamyblogs.com/35013066/the-best-side-of-4age-20v-blacktop