The Stovebolt Site Forums The Shop Area Engine Shop '64 C10 - rear axle ratio swap?

My '64 truck (lightly tuned 230cu, with stock 3-speed and back end) revs pretty high at freeway speeds and drinks more fuel than I'd like (at $7 per gallon English prices!)

Assuming its the stock 3.73 ratio I would see a useful drop in revs moving to a 3.07, which I believe was a factory option. American car spares are rare over here, so are there any other GM cars or trucks which used the same axle I could look out for a third member to swap? Even in the USA is the 3.07 differential an easy part to find?

Thanks for the advice, Limey

I'm lookin at the same thing with my 64 C-10. It's not the gas mileage, it's the high engine speed on the freeway that bothers me...so I don't drive it fast...and I just about get run over every time I take it out on the highway.

I've been thinking about looking for a 70-72 C10 rear end which (so I'm told) would have a trailing arm/coil spring setup, and 5-lug axles. This would work nicely with the 74 front suspension that I'm planning to install.

I was talking to a guy at a hot rod cruise the other evening and he suggested that a GM B-body rear end would fit...like a Caprice or full-sized Buick of late 70s-mid 80s vintage. I'm still not sure about that, since the first thing he suggested was a 76 Monte Carlo. When I reminded him that they were 4-bar rear ends with no track rod, he kinda stammered and suggested the B-body rear end. So take it for what it's worth. Personally, I'd believe it when I see it.

Good luck, Limey,

Thanks Ray. I'm really trying to avoid swapping the whole rear end as I've only recently bought some 6-lug wheels... Maybe I have to search for a 3.07 3rd member or forget it??

Anyone know a source of a 3.07 diff?
Limey

Well, you can always swap the ring and pinion. But it's a bit of a complex process. If you know someone (or you yourself) who can do this, it would be the cheapest way to go. Just get the gearset from someone...maybe on eBay or Richmond Gear. That would solve all the problems.

In my case, I'm not a differential expert by any stretch of the imagination. So I'd prefer to swap the whole rear end...plus I'm not in your shoes: I want to switch to a 5-lug setup...I already have those wheels in addition to the 6-lugs that are on there now.

Again, good luck.

Ray