Help tuning mystery motor?

I bought a 71 Duster a while back that spent most of its life as a Bracket car.
What I do know about it is:
440, 906 heads, Single Plane Strip Dominator, Large tube Fender well headers, 4" exhaust, 3:91 Suegrip, Subframe connectors, 727 with Reverse Pattern Manual VB. Running on 295/60 R15 drag radials.

The guy I bought it from had bought it from one of his employees. He did not know much about the motor other than it had a wiped lobe on the cam when he got it so he installed a new 509 Lift Cam and put it up for sale. He did not have a spec sheet for the cam.

After I Bought it, I put in an MSD Billet Distributor, 6AL-2, Rewired It as it has the typical Race car wiring, Added a new Proform 850 DP carb and took it to the track.

Initially it had 78/80 jets and 6.5 power valve.
Best Vacuum I could get was 8 inches so Dropped to 4.5 PV. Plugs read lean so I went to 80/82 jets. Timing was set at 17 initial and 36 all in at 2800.

Very disappointing. Best of 8.63 @ 80 MPH in the 8th mile.
This was on 110 Octane race gas. I ran out of that after a few passes and had to switch to 93 octane Pump gas. It slowed to 8.83 and was pinging and knocking so Took it home.

Now I am trying to Tune a Motor that I don't really know what I have internally. I suspect I have a higher compression motor as that would explain the knocking and pinging when I switched Fuel and not really sure what cam it has.

I am hoping to not have to pull the motor and tear it down to get a rough idea of what's inside. My plan is to pop the valve covers and try to use a dial indicator to see if I can figure out lift and duration of the cam in it and then pull the Plugs and run a compression check to get a rough idea of compression.

Would love to hear from others that know more than I on how they would approach this? Any and all suggestions welcome.