Just before I put the car away last fall, after going from 5th to Neutral on the highway. I heard what sounded like a huge cannon going off from the motor. I sometimes get little popping sounds in the exhaust but this was a first. Seemed to run fine after though with no remaining issues. What was this and should I be concerned with spring start-up? Could detonation really be this loud? I don't want any safety issues as my little boy and I are in the car.

 

Pre-ignition is a very mild noise, usually. Loud bangs such as you describe can usually be attributed to ignition timing problems. I'd start with a physical inspection of your distributor, make sure the cam gear and roll pin are in good shape, housing shaft isn't cracked, etc etc.

 

^ +1 my buddys 84 had the same thing happen and it was the cam gear for the distributor

 

Thanks guys, maybe time for a new distributor setup? I just couldn't believe how loud it was.