A tube mounts to the back side of the pump and runs down the valley between the cylinders. These tubes tend to corrode from the inside out. Check the tubes for corrosion, and if pitted severely, replace them. For this article, we have focused on the SOHC version used in Chrysler FWD vehicles from 1987-'97. The connecting rods, crankshaft and blocks are the same for the entire 10-year span in FWD Chryslers.
Cylinder heads are the same, with the exception of roller and non-roller cams.
Certain valve cover differences require the use of a cylinder head with a taller threaded mount for the valve cover. Either be aware of which valve cover the customer has, or supply the valve cover to fit. If supplying the alternator bracket, which is behind the cam gear on the right cylinder head, there are three different ones. There are some RWD applications, as well as FWD Mitsubishi applications. These blocks are different and some cases have been reported of modifying the blocks to fit, but this is not recommended.