[Dave at Pelican Parts]

That sounds really weird. Putting pressure on the other pushrods does not give you the same reaction as this one?

If that's the case, I'd pull the rocker arms for that cylinder, then pull the pushrods out and then the lifters. Compare the parts, see if they are noticeably different--particularly, if they are different lengths. If so, you have mis-matched parts. If not, then I'm not sure WTH is going on.

--DD