I think that the distributors on those are not adjustable , the hold down bolt goes through a slot built into the dist. and it can only go in one way. If you had the rotor on the wrong cog it wouldnt run at all. you may have carbon built up on the pistons causing predetonation, or you are using crappy fuel. Put some top engine cleaner in the engine and use hi grade fuel and see what happens. Whoever told you what you heard is wrong on everything they said. You can clean the carbon off the pistons very cheaply if you very very carefully pour water (just a trickle or you will hydrolock the motor and thats bad bad bad) down the intake while holding the idle up around 2000 rpms. the water will break up the carbon. You can also take it to a shop and have a motorvac performed on it. Seafoam is also another type of top engine cleaner that works well.