Developed a tick

Ok,... So I did a little investigative work last night. Pulled the intake and looked at the cam and lifters. Cam wear looks fine by the wear pattern. No excessive wear on the lobes, and the pattern looks like the lifters have been riding correctly and turning as intended. Lifters look fine and still have a crown on them and a nice faint circular wear mark. Everything look just how I would expect for a motor that only has a couple thousand miles on it.

So,... I decided to check out the amount of preload on the lifters. The lifters I checked were fully pumped up and very difficult to compress. To check preload, I tightened the rocker shafts back down, then slowly loosened each fastener in very small increments until I felt movement in the rockers. Too small of a gap to get an accurate measurement between the rocker shaft and the risers, but I thought of another way to calculate it.

I only had to loosen the rocker shafts bolts 1/8 turn before I started feeling play in the rockers. The bolts have a thread pitch of 16 threads per inch, which means 1 full turn is 1/16th of an inch, or .0625". If I only turned it 1/8 of a turn before I had play on the stamped rockers, that should mean I only have about .0078" (.0625"/8=.0078") of preload on the pushrods and lifter. That doesn't seem like enough. One little bit of difference in rocker stampings, or a minute amount of wear would explain my ticking I am hearing.

So my question is this,.... Does it make sense to measure my pushrods and get some that are a bit longer? I pulled all 8 pushrods out of the motor so I could measure them all and see what the min and max lengths are. I'm thinking I need something .015" - .020" longer pushrods to get the proper preload on the non-adjustable stamped rockers.

Can someone tell me what the preferred preload amount is on these motors to confirm my theory. In the past, on adjustable rockers, I have always taken out all the lash, and given an extra 1/2 to 3/4 turn, which in this case would put in .031 - .046" of preload (.0625" x .5 = .031" .0625" x .75 = .046"). If I were to get .020" longer pushrods, it should put me about .028" of preload.

Opinions??