Cam chain tensioner not so tense

[Hotshoe]

I'm working the bugs out of my '67 CL77 with 18K unverified miles on the odometer and would appreciate some advice.
I hear an unhealthy rattling sound that starts when I first roll the throttle on and though it's harder to hear as the revs climb, sounds like it continues till I let off the gas.
I set the rockers at .004" and checked them and the compression on both sides is good so it's probably not valve noise or piston slap but I'm pretty sure the rattle is top end noise.
I also checked for loose bits on the chance that something was harmonically vibrating but didn't find anything.
When I tried to adjust the cam chain tensioner I found the pin inset into the tensioner body about 3/8" (picture attached).
As I remember the tensioner pin should actually be extended out a little, so I'm thinking the cam chain has stretched and the tensioner could be bottomed or worn out and the rattle I'm hearing is cam chain lash.
Unless someone has a better idea, my next step will be to pull the cam chain tensioner assy and see if that tells me anything.
Thanks in advance for any advice or guidance from the group on this.

[e3steve]

Looks to me like the roller has probably disintegrated. Don't run the motor until you've pulled the tensioner out (so-o-o-o-o easy) and verified its state.

If it has broken up then there will be loads of hardened rubber bits in the oil and possibly oilways (but they should have been caught by the oil pump gauze strainer). Oil pump out and total flush-out.

[Mike Mullins]

I just pulled my engine for the same reason. Found one of the starter mounting bolts had backed out and was rattling around inside the cover. Was a good excuse to replace a tranny bushing and x the gears.
Mikeyrx