Need some help with diagnosis

IMO
A lo-compression 318,
at or near sealevel,
running a compression test of 140 on all cylinders;
means that there is nothing wrong with the cam-timing.
And probably nothing wrong with cam, nor the valves.
So then, since it began DURING a drive, and
started at zero mph,
My guess is;
that there is a problem with the AFR, which could include water in the bottom of the carb being picked up by the accelerator pump.
But could include coil hi-voltage loss across the terminals.