63 gmc gearing

[62gmc910]

Originally Posted by Captainfab

Well someone is blowing smoke up your a$$. There are 3 or 4 companies that make limited slip and locker carriers for the truck 12 bolt. You can see some right HERE Those new ones may not be in your price range, but used ones can be found on ebay, Craigslist, etc. The GM truck 12 bolt was used from '63-'81 ( I used to think it was thru '79) in both 2wd and 4wd. So there were a larger number of these produced over the years, and should not be too hard to find what you need.

Also it isn't always about obtaining the lowest cruise rpm's. It is more important to get your engine in it's 'sweet spot' rpm wise where it is most efficient. Finding that may require some research into factory combinations, and asking others what works for them. That's where this forum comes in real handy.

thats pretty much what I was gonna say