ABC, i guess i'll be in the minority on this thread, but have you considered just staying at 6v and fixing the grounding? the 6v system works pretty well, for me at least.
just my 2cents.
tony


Overland Blue, 1953 GMC 1/2T, 100-22, 228/1bbl, 4sp/4.10 6v, shortbed/fender side/5-window.