i had that issue once and it was my blue/orange elec.ignition box losing ground. if i wiggled it, the car would start again. of course, i was young, so i didn't re-ground it. i just kept wiggling it. :D
haha, don't short change that 318. they have more get up and go than most realize. my '68 fury has a 318 in it and it hauled a little. do a little headwork and those suckers open right up. i'm building mine at the moment, and expect 300-330hp out of it in a very manageable little package...
this is so weird. the purchaser made a thread about this on facebook in a plymouth fury owner's group. now i'm seeing this on your end. i don't believe i've ever heard a more tragic car tale in all my years in the hobby. it's just awful.