Quote Originally Posted by VikingRed View Post
To begin with it had some valve bank (not quite sure if that's the official term, but as accelerating you would hear crackling noise) and when heated it got worse. Long story short after over heating it sat on the side f the road for a few hours, it now misfires on two cylinders. I plan a engine overhaul but before I start do you have any suggestions of what might be causing the two problems? The misfiring and Valve crackling?
I'll take a S.W.A.G.
The motor is detonating and you've either cracked or holed a couple of pistons or smashed the top ring lands down, pinching the rings so that they cannot build compression.
Detonation in a motor has the same effect as swinging a sledgehammer down onto the pistons over and over. It has several causes, including running a high-compression motor on fuel that is insufficient in octane to keep the motor from detonating.

When you get the motor torn down, come back on this forum and tell us what you found. Most of us on here can lay out a plan for the rebuild that will preclude this happening again. We've been there, done that.