The ding on the piston does not look severe enough to be worth replacing the piston over. One might want to debur any sharp edges at the ding. The valve that got tagged is another matter. The head of the valve is likely bent enough to prevent a good seal and should be replaced.

I agree that the valve stem seal was off the guide, but I don't see this being the cause of the valve piston interference. You need to understand the cause of the problem and correct it.

Eugene

 

well i have another head that i got rebuilt and put on so im not even gonna use that head i might just scrap it idk

 

and it was sticking open causeing the interference