Death of a /6

i had a '65 dodge truck with a /6 and in the year i drove it i never checked any fluids or changed anything. the guages did not work and it smelled like it was overheating when i was on the hiway. it never ran rough or anything. and always started. the new owner said it had a cracked head and 3 cylinders had horrible exhaust leaks lol. still ran perfect tho lol