Those old motors were built to last forever, and yours was a FIRE TRUCK, so you know it was built to take more than it's fair share of hard running.
My '46 2 ton needed the gas tank flushed out (because somebody stole the cap), the radiator flushed out (because somebody stole the cap) and a new flywheel ring gear (you guessed it, because the "cap" was missing).
But with some fresh gas and a new battery, that thing fires up and runs smooth as silk with THE ORIGINAL PLUGS, WIRES, POINTS and ROTOR.
I should mention that it was parked in 1976 and hasn't been so much as cranked over or moved until 2005.
No, these trucks were built in a different time in American history, when giving customers a real value for their money was the #1 goal. Not building something that will force you to buy a new one every 5 or 6 years.
Besides, it's not like your going to the show full throttle with a tank full of water and a troupe of Russian dancing elephants on the back.