Cant remember exactly what the B is, but TDC is Major Useless CENTRE for for timing. All 20V's, no matter whether on the coast or highveld should have a btdc of ten deg. Meaning your stock timing need to be established at ten. 4AGE 20v ITB vacuum instructions on Intecracing.com https://toyota-4age-engine-for-sa49135.blogsmine.com/35049309/top-latest-five-toyota-4a-ge-urban-news