Hi,
Lifter preload might be your culprit. I am in the final stages of engine assembly with my regal,and am using comp cams mildest hydraulic flat tappet cam. I believe it is 206/206 and .425 lift. Anyway, the lobe circle is different on my cam, and my stock pushrods were about .060" too long. I had something like .090 lifter preload, and comp recommends .020-.040. There are several ways to correct this, but as I am putting it together with stock heads and rocker arms/shafts, I elected to change pushrods.a friend suggested smith bros.,and if you check it out, they are pretty good.Anyway, for about $125 shipped, they made up a set of proper length rods, twice the strength of original,and they tell me if I have problems, they can fix it.I installed them,and by the dial indicator, I now have somewhere around the .030 that was recommended. We shall see, soon,if the valves are noisy.
You know, a bunch of different stuff affects this parameter, including your cylinder head /metal removal, block deck height, rocker arm and rocker shaft wear, and cam and lifters. Get it right, then noise chances are lessened.If I had just bolted it together with all that preload,lobe failure and also lifter problems could have been the result.Tick, Tick, or worse! This is food for thought; good luck with your trouble....