The Stovebolt Site Forums The Shop Area Engine Shop 5.13 rear gear swap

I have a 1951 1 ton chevy with 216 engine, original 4 speed tranny and 5.13 rear axel ratio. I have axcess to what is discribed as a 1972 chevy 3/4 ton rear pumpkin with a 3.54 ratio. Will this bolt into my existing differential? I do not haul loads with this truck and would love to drive a bit faster than the current 45 MPH. I must add that for rear tires, I am running 255/85R16 tires. Thus equiped, will this ratio be Too LOW? Thanks for any input, Jerry

That ratio should be OK. It's also somewhat rare. I've only seen one myself. The entire third member will swap right in, no need to change the entire housing.

That's right on rare. I've never even heard of them or seen them listed in any chevy list for this axle. 3.90, 4.10, 4.56, 5.13 I've heard of, but never a 3.54. Are you sure it's a GM and not an International? They look similar.

If (and I mean if) it fits, you'll have plenty of highway gearing... but you can forget about using your truck as a 1 ton. You'll have little low end grunt, even if you have the granny 4 speed.

Unless you plan on swapping out your tranny for a 5 speed, I'd definately get that 3.54. You may not be able to pull as much but it will help your top end and streetability, and make life easier on your engine. If you later decide to change things I'm sure you can sell it to someone on this site and recoup your cost.