Dear Mr Hoyt;
As it was one of the first, it probably was in a 1 Ton (C-30) or larger. I'm not sure if they were available in busses then or not.
An 'asbestos blanket' from a Welding Supply House wraped around the front head pipe(s) will stop the heat.
It's that with 'Hot Rod' type engines it looks so out of place etc. These too, are maintained much more carefuly than 'normal', so the filter concept is just academic.
I never run a filter on any 'early' Chev 6 because of this. On the 'other side of the coin' I use a 2 Qt. one on later & V-8s which doubles the change interval with commercial oil.
Fram PH-1 has the by-pass valve.
Good luck.
