Are What RPMS should a /6 be at while driving 55?

i've had /6 for ever an a day ran them hard too . i . ive use an abused .ck the oil one day cause the oil pressure was bouncing off 0 took 6 qts to fill it back up oil pressure came back to 40 psi ( had been doing that about a week) i drove over a 100 miles aday back an forth to work in my 82 dodge pick up i had over 500,000 miles on it before i retired ol yeller . it was a 100 still is, its setting out back resting . went to the scrap yard one time had over 2200 lbs of copper wire in it .had to put wood blocks between the springs an body cause the springs were bending backwards . last week end the boy ask if it wood still run ,sat for 2yrs pour a little gas in the carb hook a batt to fired about the third revolution /6 are as tough as they get in my opinion . never blew one up . wore them out first, when i retired ol yeller 65mph was top speed flat on the floor .empty