It's a roller cam with new Ford Racing roller lifters. That's the thing that has me puzzled, the ONLY used part on the entire engine is the block and it has been totally remachined. Every other part is brand new and matched. I've built engines with lots of used parts and haven't had this sort of problem.

The cam has it's front plate installed, so I don't think it is walking. The one thing I did notice is that my new Comp Cam timing chain now has some slight slop in it, where it was tight when I installed it. I know they stretch out a little, but this seems too soon.

Don