440 Engine tuning suggestions

Good Morning FABO,

I have a 440 that was rebuilt about a year ago and need some help and suggestions about a "dieseling" after i turn the key off.

Its a 69 440 block with the following
10.7:1 compression
Stock 440 source heads
holley street dominator dual plane
Howards cams hydraulic roller 230/236@.050 .545 lift
Mopar Performance electronic ignition distributor with orange box module
Holley stteet avenger 770 vacuum secondary
Dougs headers
champion spark plugs recommended by 440source

The issue I am having is it diesels after I turn the key off. I have played around with the timing but unless I drop the idle speed to like 650-700 in park (which drops even further in gear) to where it is struggling, it will always diesel.

What should my initial base timing be for a performance engine like this?

What should it idle at in park?

Is my compression ratio too high for california 91 octane and contributing to this dieseling?

Other than the dieseling after shut off, it runs great at cruise, part throttle and WOT. Car does not run hot either.

Ive built other engines before and never had this problem. Kinda frustrating.

Thank you to all in advance for the help