New Battery Cables Installed-No Start!

[MikeIIDC@domain.elided]

Okay, I put on the new battery cables (on the '74 WM, 2WD, 392, AT).
They are the best I could get at the local chain shop-GRAND AUTO, I
think is where I got these.  They are 2 Guage, with the negative being
15" and the positive being a 48" length.  I fired the thing up and it
ran, fired it up again, let it die, turned it over about twice-no start
anymore.  Same thing as before-acc lights come on, but no starter
turnover.  To refresh-once again.  I have changed ignition relays,
flipped these over myself (let them hang from the column and do it with
a screwdriver to make sure they are moving as far as neccessary),
changed the starter selenoid twice, changed the battery cables, and
played with the gearshift lever position each time I tried any of this
stuff to see if it will go into any sort of proper position.  Every time
I let it sit for more than twenty or so minutes, it will start again.
This always had me thinking Gold Box, but I have been discouraged fporm
this line of thinking by you fellas, so I have stayed away from that.  I
ordered a neutral safety switch today that should arrive by tomorrow
afternoon.  I can only hope this is it, as I am running out of ideas.
Does anyone have any last things to add before I go baseball bat hunting
and beat the living s*#! out of my *%$+ing Wagonmaster?  I love the
thing so that I hate to destroy it, but I can only take so much!

Thanks in advance for any suggestions/therapy!

Michael