Should be no problem as Pontiac did not make a 305 . Sure you don't have a 301 ? If 305 then original Chevy stuff will work . If 301 , you will need Pontiac brackets . Also , since no more R12 , you will need to convert to 134 . Seriously consider getting this done at good repair shop - one you know will not screw you as this needs to be done properly in order to cool correctly .