440 what am I missing here?

I would do what TTI5.9mag says with the timing before warming it up for the compression test. Or lock the distributor rotor out and set it at 32 degrees static ignition lead and use a start retard. Or mark it and leave it on the edge of loose so it could be turned back to crank it without bucking against the starter. Take it out and see how much improvement you have. It should certainly help some.
But, there are worse issues at play here.
Cam specs from TFS.
https://static.trickflow.com/global/images/chartsguides/t/tfs-61602003_sn.pdf
The intake closing event at 72 degrees ABDC is the real killer here. Advancing the cam 4 degrees would help some, but the answer is it probably needs more compression. More converter is a given, and probably more gear is a certainty, or swap to less (or a cam with an earlier intake closing event, not necessarily smaller) camshaft. And I would would probably change over to an Edelbrock performer RPM with an HVH 2 inch super sucker carb spacer. It may not look as racy, but I promise it would add a significant amount of low end torque without losing anything on top right now. If summit is helping out on it, this converter would also help, although PTC or Precision of New Hampton may come in cheaper for a more efficient custom built converter.
FTI Performance SR Series Torque Converters SRC80828
If you wonder who makes this rebranded cam for TFS, and what they recommend on stall (and they say gears... yeah it has to have rear axle gears to go anywhere, but what ratio range would be helpful! :wtf: :realcrazy::BangHead:), here it is.

Hydraulic Roller Camshaft; 1959 - 1980 Chrysler 383-440 2800 to 6600 Howards Cams 723235-08 | Howards Cams