Raced in events from 1929 onwards, achieving particular success at Altoona. Bost largely appeared at either dirt or board oval tracks, with a couple of good finishes in both 1929 and 1930. 1931 saw a concentrated and sustained effort with a number of races; his best results were at the aforementioned Altoona track, coming third and fourth in two races on the same day. Paul carried on racing until 1935, when he was a relief driver for Mauri Rose at the Indianapolis 500. That year was the year he got married and he honoured a promise made to his newlywed wife that he would immediately stop racing upon marriage.

Biography last updated 5 Feb 2018