I don't think there is a 3/8- 14 tread on any Stovebolts. Or that size was ever produced for anything.
It is probably a 1/2-13 thread.
When I mounted a 235 on the engine stand, I used 1/2-13 bolts.
In fact, that is the only size bolt I have used, be it GM, Ford, or Chrysler.

No DB, there are no stupid questions on this site.
If it saves someone some hurt or money, we are here to help!

Don

1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
'46 2-Ton grain truck | '50 2-ton flatbed | '54 Pontiac Straight Eight | '54 Plymouth Belvidere | '70 American LaFrance pumper fire truck | '76 Triumph TR-6
Of all the things I've lost in my life, I miss my mind the most!