Hi, Check the lash pad to see if one of the sides is broken off. If one side is missing the rocker arm will slide off . Regards David.

Nope, still has both sides.

I think carrott is right, at the very least you have a sticky valve. This post may help you.

http://www.classiczcars.com/forums/showthread.php?p=258354&highlight=stuck+valve

I haven't pulled my head yet so i don't know what causes my issue. Like yours, it sat for years.

Blah, I was hoping to not have to pull the head, but everything seems to be pointing that way Oh well, at least it's easy to pull, or at least looks that way.

Well, I finished resetting the valve lash yesterday, cranked it up and it seems fine now. I cranked it up and didn't rev it much until it got a little heat in it, but it did good, no clacking from the valve cover at least We'll see how it does, it's a long way from being on the road so if it continues to mess up, not a big deal, I'll just pull the head.

Just be sure to wedge the timing chain!

Just be sure to wedge the timing chain!

Will do, thanks for the reminder