i m about to buy a used y pipe but it doesnt come with anything else. I think i ll need 3 gaskets so where could i buy the gaskets from? I searched on line but it does not give me any gaskets thats connects the header to the y pipe, only a gasket connecting the y pipe to the catt.

 

Autozone, advance auto, Napa, O'Reilly's, etc.

Ask for an exhaust manifold (or flange) gasket, they're about $2 each at Advance around here. It's just a circular crush ring that lays in a small depression in between the y-pipe flange and the exhaust manifold.