I think that one purpose of dielectric grease is to prevent the conduction (especially arcing) of electricity (also prevents rust, corrosion, oxidation, and rubber parts sticking to metal/ceramic parts).
If you want to enhance conduction and are not concerned about arcing (such as battery cable connections to the battery and/or frame-ground), then a conductive anti-corrosive grease will serve that purpose.
http://www.tessco.com/products/displayProductInfo.do?sku=437469&eventPage=1 http://www.omgtr.ca/technical/General_Technical/grounding.htm Eastwood Supposedly, 6v vehicles had 2 gauge battery cables and 12v vehicles have 4 gauge battery cables. Often, people have the 4 gauge cables on their 6v vehicles. This is inadequate. Many people suggest 1 gauge battery cables for 6v vehicles and some use 0 or 00 (1/0; 2/0) gauge battery cables. Such cables are available (or can be made) at a good truck or tractor parts supplier. Be careful, most people behind the counter think that a smaller number means a smaller thickness of cable.
A few months ago, I finally got tired of hard starting (especially with a warm engine) and I installed 2/0 gauge battery cables (positive and ground). The engines spins very nicely now - hot or cold. The thickest braided ground cable that I could find was 2 gauge, so I used 2/0 gauge round cables.
It seems that 6v GMC New Design trucks ran the ground to the transmission (and, I guess, a ground cable was then run from the transmission/block to the frame). Chevrolet Advance-Design trucks ran the ground from the battery to the frame (behind the battery box) and then from the frame to the clutch-housing (to the bolt that holds the foot-starter mechanism to the clutch housing). There is also a ground cable from the head (behind the distributor) to the firewall (this is shown in the radio installation manual. I think).
