Not from '64 or '65 Dodge or Plymouth Tech service manual. Best read from the correct service manual for these. They run about $55 for a repro book. Used you can usually find for less. I think its the first purchase that should be made after buying the car.
The max on a grade 8 5/16 bolt should be about 18 ft'lbs which is about 220 inch-lbs. Breakage or stripping at 25-30 ft-lbs
IMO, an Inch-pound torque wrench is essential to any work on an old 273. Most torque wrenches, (Unless its an expensive one) arent accurate below 20.