575 hp @ 6300 rpm

OK so that is a spacer on the cam. It looks like a flat washer that has a section cut out to allow the pin from the cam gear to pass through to the cam. The cam gear does appear to have a spacer built onto it. So is the flat spacer not needed?

So I bought a 73 F100 that has been sitting for years, but has a 360 that was rebuilt not long before the owner passed away. I was told that it had always " not ran quite right" after the build and the previous owner was working through that. The last thing being changing the distributor setup from points to electronic. So, I removed the valve covers and found problems at the #2 cylinder. The pushrod on the intake side is bent and the pushrod on the exhaust side sits about an inch away from the rocker arm. After pulling intake I found the lifter for #2 exhaust was broken into several pieces. All of this is bad, but I also found that the cam can be be moved towards the back of the engine about 3/4 in. That seems like too much movement. Any thoughts on what I need to look for to be causing this?