erratic timing on 360

I’ve been having the same issue of timing jumping up to 8 digrees at 3k rpm on my 340. @yellow rose has recurved my distributor twice while using my digital 6AL box and has not seen the timing jump on the machine. We’ve used a few different timing lights and shows the same jump on each of them. I’ve not been driving my car nor had time to check the chain or oil pump shaft as noted in prior posts. @lead69 and @yellow rose along with some other friends have been seeing a lot of crappy chains in the last year or so with very little time on the motor the chains are having serious stretch... now I know I’m not the only one having this issue...