Well, i too had the the "bent pushrod" thoughts going threw my head due to a ticking that was in my 99 ws6. It seemed to only be coming from the drivers side. Well i was getting really irratated with it today so i decided to diagnose it myself. As i looked over the engine i listened closely to where the "Tick" was coming from. I have MSD spark plug wires on mine. I was looking really close down by the manifolds where the "tick" was coming from..I pushed on the 2nd from the rear spark plug wire and it stopped! i thought thats weird. I looked closer and come to find out the heat shield that is around the spark plug is loose and is hitting the manifold...giveing that all fearful "Tick" sound. I laughed and said to myself wow..what a relief. I suggest anybody with a ticking sound might just wanna take a look and make sure ones not loose. WOOHOOO!!!!

 

I had a loud ticking on the drivers side, especially under load. I checked all wires, etc. and was thinking lifter like you. Then I pulled the #1 plug and it was gapped at .023 . So I regapped it to .055 and re installed it. The tick was gone and the car was more powerful.