I don't think any of the info for the new '98 engines will help him.
The changes for '98 are, "valve train, cylinder head configuration, intake manifold configuration, timing belt covers, cylinder head cover, engine cooling, thermostat location, crankshaft configuration, oil pan design, piston design, and accessory belt length".
"The engine valve mechanism on both the 3.2L and 3.5L engines are distinctively different than previous model years equipped with dual overhead camshafts. Both the intake and the exhaust camshafts are driven by internal idler gears instead of a chain mechanism. The idler gear to camshaft gears are driven at a ratio of 1.333:1; therefore, it will require multiple turns of the idler gear to equal one full revolution of the camshaft gears. Also added is a spring loaded sub-gear assembly. This feature is added to take up back lash in the gears to help reduce gear whine."
Planet Isuzoo would probably be the best place for help on earlier engines.
http://forum.planetisuzoo.com
Mark Griffin