The two vents on the sides of the dash cluster r those heater vents or ac vents?If u have ac where does the ac air blow from?Also what is involved with replacing those side vents?

If you're talking about the round vents on the 67-68, I believe the AC is also routed through those vents. They are a real PITA to remove and replace.

no hes talking about the rectangle vents on a 69

On a non-AC car they are the upper astrovents (fresh air from cowl). On an AC car they are the bi-level setting on the controls. Replacing them requires the housing to be removed from the dash, easy, but you have to take a lot of parts off to get to the screws that hold them on (dash, dash housing, glove box). Once you get them out of the housings, they normally require new felts to hold them in place.