While installing the 401 In my J10 I decided to replace all the censors and such and ran into a problem locating a ported vacuum switch or as the shop manual calls it a CTO (coolant temperature override). This is the 3 port vacuum switch that sends manifold vacuum under 160 degrees and then ported vacuum over 160 degrees to the distributor. There can also be a 2 port EGR/CTO switch that controls the EGR, not to confuse them. The "Standard" number is PVS10 which is discontinued for the AMC's. The only number I found on my old switch was Q23. Did a little digging in the Standard book and found one for a Ford application (PVS20) or (Duralast E941 switch interruptor) with the same specs (thread size and heat range). When it came in it also had Q23 designation on it. They should update the books for application. Just thought it might be of some interest to others.