You do NOT want the older style heads on any 92 series. Look at the casting below the rocker covers on the heads and the 'dog-bone shape will be there. The Silver engines had a beefed up engine block and the heads were the 'dog bone' style. Some fire trucks had them used for some reason, the ones I see nowdays are not installed with a shutdown flapper. The only engines I have seen still useing the flapper are engines in use in the oil field or where there is another fuel source possible like a gas or vapor. If 1 injector seizes the other 7 will go to no fuel when the shutdown is used on top of the governor. The emergency flapper was removed because of the new spring racks in use.
