Years ago, I had a Southwind with a 454 that regularly ate fan belts. I could either set it too tight,which caused the belt to break in a short time, or too loose, which caused it to slip and the battery to go flat as the alternator was slipping. I bought a belt tension gage and finally got the belt to last for a years worth of driving (about 7k miles). Mine was an '83 and shortly after Chevy went to a double belt configuration. A single belt was simply marginal when driving the alternator, AC, water and air pump.
The other issue with that engine was that it regularly went through spark plug wires. Finally went with NAPA lifetime wires and replaced them almost annually. Routing was critical to keep them from crore-firing. If a wire from a firing cylinder was routed next to a wire from a cylinder in intake cycle I got "sneezing" where the Intaking cylinder was fired. This occurred under full throttle.
Dick L '04 HR Imperial