I think it may depend on the truck capacity. I believe on 1/2 ton trucks it's possible to swap the ring gear on the flywheel. At least I've seen that posted here before. The 12V ring gear is 168 teeth versus 139 teeth on a 6 volt.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
