Solid roller lifters...

512Stroker said
That plug is lean
Heat range looks good
Looks like the timing may be a bit retarded.
This should help ya figure it out
FBO Ignition - Home of the HRR688 - Spark Plug Reading

This photo better shows what I got in the end. It’s part of larger frame so the quality of image is affected. I need to drive a bit and check the plugs again.

Thanks for link, I think I saw this website before.