Just completed the rebuild and initial break in of my 440 in a 67 Coronet. Rebuild details are in https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1638758/1.html

Quick rebuild summary:
- 1969 block 0.030" over
- 906 iron heads at 82cc
- 0.020" head gasket
- KB236 piston
- Eagle rods
- 509/292 108 cam
- Torqer single plane intake w/ 1" spacer & no exhaust xover
- 4150 (700CFM) DP Holley w/74 prim, 84 sec jets
- Mallory Hyfire w/ Promaster coil & Sidewinder wires
- 15 degrees initial timing, 22 mechanical for 37 total at 3k RPM
- Autolights 85's are gapped at 0.040"
- 1 7/8" headers
- 2.5" dual exhaust w/ xover


So far she's running excellent with Sunoco 93 and no audible detonation.

Based on the plugs, it appears timing is ok, but suspect the carb is a bit on the lean side as I hear a slight misfire at cruising speed and there's a lean surge feel to it.

I've attached a few photos...would love some insight and feedback on the plugs.