A factory 305? In a Cutlass? that strikes me as odd. You may want to make sure that it is a 305 and not a 307 olds. If you have a 307, chances are that you have too little timing to start with.Easiest way to tell is to look @ the distributor/intake relationship. If you have to remove the distributor to remove the intake, its a 305. If the distributor is seperate and the intake clears it without having a hole drilled through for the dist, its an olds motor. If its a 307, i can help you out there. If its a chevy, listen to everyone else