I've had my Unique on the road for about 2 months. I've just got a few hundred miles on it; mostly from sorting out runs. The engine is a SA 351w with a hydraulic lifter cam and roller rockers. I've enjoyed driving it and the engine has been great. But it has started running rough and the engine has developed a fairly loud, rapid, metal-on-metal tapping sound. The timing is where it's supposed to be. Oil pressure is fine. Bill and Lyle have been talking me through valve adjustments; thinking that is the problem. I've been through about a dozen rounds of valve adjustments. I have all the rockers set at zero lash. I have also tried tightening the rockers down varying amounts past zero lash, but the sound is still there. I'm concerned about potential engine damage, so I've decided not to run it any more until I get this figured out. I plan on continuing my discussions with the SA folks next week, but since it's the weekend I was wondering if anyone out there has any thoughts as to what's causing the tapping sound? I'm hoping it's nothing major, but I'm a little worried.

DU