I went back and re-read his question and this is what I found.
The throttle-body fuel-injected 318 motor had a few changes for its model year (1988), which would come to the 360 in 1989.
First, Chrysler finally switched from standard hydraulic lifters (and matching camshaft) over to a roller hydraulic lifter and a new matching camshaft. The roller design allowed for a steeper cam profile, and thus a more precise valve-train actuation.
Second, the 2 barrel TPI fuel injection intake replaced the carburetor. Third… the heads were different; the basic casting is the same, but the fine points were not. To make better use of the fuel injection, swirl intake ports were introduced. To accommodate a slightly changed pushrod angle (the new roller lifters were taller than the standard hydraulics), the push rod guide holes in the cylinder heads were changed from roughly 0.5 inches to a published 0.66 inches (Dodge DW Series Truck Factory Service Manual, 1988). Upon measurement, this was confirmed to within an accuracy of 0.01 inches. Push rod length changed from about 7.5” down to 6.78”, and diameter shrunk from 0.360” to 0.3125” (again to accommodate the changed push rod angle).