to be exact the last 400 pontiac was built in 78 the 79's were just what was left over after they ran out in 79 they were replaced during the remaining production year with 403 olds motors if you chose a 6.6l engine.you could get an automatic behind the 400 pontiac in 79 i have seen several case as a matter a fact i am helping restore a red automatic 79 TA w/a 400 all original.