still having problems, need advice please

67 dart with 69 340 engine, fixed all wiring from bulkhead (including bulkhead packard clips), cleaned every ground I could find, have added wire around and headlight relays (thanks Ron). here's the numbers:

new battery and new alternator (50 amp square back Chrysler).
tests:
12.67 at battery before starting.
start engine, at idle:
14.34 at battery
14.30 at starter relay
red from battery 14.20 at bulkhead
coil positive 11.26
ballast 13.7
alternator stud 14.6 (goes down as engine warms up)
alternator stud warm engine 13.91/13.98
when electric fan stops 13.85/13.75

negative battery post to alternator housing 6.0V (5.1 @ 1500 rpms)
negative battery post to block 0
negative battery post to ground strap at block/firewall 5.5V (same at 1500 rpms)
negative battery post to ground wire at frame 3.0 V (same at 1500 rpms)
negative battery post to ground wire at block 0

then ran high idle (1500 rpms)

13.22 at battery
13.41 at alternator stud
13.2 at starter relay
13.22 red at bulkhead
coil positive 11
ballast 12.95

then high idle with load of headlights, wipers, heater fan, flashers, and radiator fan cycling (did put both power to fan with relays, along with switch to starter relay so it would continue to cool after engine is shut off with key, is that alright?).
battery 13.16
ballast 12.24
alternator stud 13.10
then car died before I could finish.
checked battery quickly while fan was running 12.38, when stopped 12.59
no fuses blew, 40 in black from alt, 30 in red from battery, 40 in wire around (sorry Ron, cut myself short with the wrapping and had to add a fuse in the fusible link).
started engine again and battery was 13.10, and engine did not start easily.
the previous night I was doing checks and would only reach in the window and hit the key and it would start immediately.

any help appreciated, if you need other readings, just let me know.
thanks to all that have gotten me this far, it has been a long journey to be sickened by having continuous problems (whining over). thanks again to all.