I think Freedo's right on the money!
Even if your truck is still 6v, You should be able to rig up some bed roll stop lights.
If I remember correctly Carolines truck did a posting on this a while back. Jim made them himself rather than pay $100+ dollars for manufactured units. I agree with Highflyer though, the L.E.D. units are MUCH brighter and a third brake light wouldn't hurt either. I'd rather give up a bit of originality and be safe.
The thought of some Dumba$$ running into the back of you is just plain scary! big_eek

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.