Yes thats what IM thinking too. well this is it I doing the Intake gasket checking all vacumm ports and resealing all checking the advance in the disy. going thrught it with a fine tooth comb.will let you know what i come up with.also going from 65 pri and 68 sec to 70 pri and 72 sec.a 50cc acc pump and a bigger squrter.the heads are 3964290