I just got my 1968 chevelle out of the body shop where it has been for the last year(whew!)before that it probably has not run for for a couple of years. The engine is a 327 with hydraulic lifters the engine was rebuilt about ten years ago but the car was rarely driven as it was stored in the garage and i used to start every now and again just to keep it running. I gave the car a tune up and it seems to run ok however there is a slight valve tap. I changed the oil and filter and have driven it ittle bit to see if it works itself out. I suspect a sticky lifter being the car has not run for so long. I am looking for some advice on how i should proceed in diagnosing this symptom
I don't want to try and tighten the valve adjustment down for fear the the lifter will eventually pump up and bend the push rod. any tips will be greatly appreciated

Thanks
Chuck