This from Mike Summa for #TBT:
For TBT-The Clark Oil Refinery in Blue Island once utilized this 1960’s GMC/?, I am guessing National Foam with unknown specs. Please feel free to add any information. (photo courtesy BI Historical)Mike Summa

photo courtesy Blue Island Historical
#1 by CrabbyMilton on June 13, 2019 - 11:45 AM
I think GM built this chassis/cab until the late ’70’s but the FORD C SERIES was by far and away the most popular.
However, this one appears to be a decent looking no nonsense rig.