its a vacume advance canister, there is a diaphram in there that uses a vacume signal from the carb to advance the timing (the distributer also has a mechanical advance that advances the timing depending on how fast the distributer shaft is rotating). the distributer that you have on there is a mechanical advance only (such as the 009)...it only uses the distributer speed to advance the timing. a lot of people like the single vacume distributers cause they tend to be a bit smoother (vacume is right there right now when you step on the gas) so the distributer adjusts much quicker, where as the advance only has to spin faster to make any change in the advance curve. ever heard of the notorious 009/34pict3 flat spot?? the vacume distributer also tends to yeild a little better gas mileage (usually about 3-4mpg)...but put that with the motors added smoothness...how can ya go wrong?? hope this helps ya and that someone can add to this. basically your fine running the one you got on there now...just plug the vacume port on the carb with something (rubber cap works well). happy hang overs guys...i mean new years!!
