the 3 window cab [no corner windows] was the standard [cheapest] model, the 5 window cab [w/ corner windows] was an extra cost option that most farmers and working men didn't opt for .... for different Advance Design year details check out the GM information kits here [click the 'show' after trucks]

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics