Yes, 8 11/16" pushrods are quite short for a typical Pontiac V8. One possible reason would be roller lifters (aftermarket, either solid or hydraulic), which are typically quite tall. Have you had the valley cover off to see what type of lifters it has?
The only way to know for sure that pushrod length is correct, is to check the geometry of a rocker arm tip against its valve tip. During an open/close cycle of a valve, the contact of the rocker arm should remain very close to the center of the valve tip. If you search these forums' archives, you'll find lots of discussion of checking geometry. If you have solid lifters, you can definitely check geometry with no more disassembly than a rocker cover off. However, with hydraulic lifters, you would normally need to substitute a solid lifter (same length as your hydraulics) or make one of your lifters into a "temporary solid", by packing the inside with aluminum foil or whatever (requiring removal of intake manifold and valley cover). You could, of course, get real lucky and locate one of your hydraulics that has a very slow bleed-down rate, and check geometry of that one (avoiding pulling anything apart).
|