Some cars leave a paper trail; the Pontiac Custom S left a name and a place in Pontiac's list. What follows is what can be said with a source behind it.
Where it came from
The Pontiac Custom S was a one-year only Pontiac nameplate offered during the 1969 model year car as a replacement for the "Tempest Custom" trim level in the Division's line-up. Originally to be called the "Pontiac TC", it was slotted between the Tempest and LeMans in price and features.
In context
Nearby in the Pontiac catalogue sit the Pontiac 2+2 and the Pontiac 6.