The Stovebolt Site Forums The Shop Area Driveline Too low too slow

Now that I have great working breaks. I’d like to switch out my gears to get a little more speed.

I have an original 1949 rear axle in a 3600 3/4 ton. I’m hoping to find a set of gears to swap out the original set if there is such a thing. Currently my top speed is 47 mph.

Can anyone point me in the right direction to purchase these gears?

Thanks Don

Those gears are sold by the same company that has powdered unicorn horn and bottled moonbeams. They just don't exist. A complete center section from a HO 72 axle from the late 1960's- - - -early 70's will bolt in, with a 4.10:1 ratio, but those things are also very scarce. That's probably because a lot of us dirt track racers scavenged them up and wore them out in the 1980's.
Jerry

Check.
4.10 is as good as you can hope for in the original axle housing.
After that faster gears require an entire axle swap.
Or an overdrive transmission.

What do I have now?

Don

Probably 4.56:1 if it's a 3/4 ton. There's also a 5.14:1, but it was mostly in 3800 1-tons.
Jerry

Sorry, though I was replying to a post where you said you had 4.10 or 4.11.. either I was mistaken or the post vanished.

4.56 is most likely in a 3/4 ton

We used to put 17" tires on our 3/4 tons with 4.56 rears and run them 65 to 70 all day long. If your engine is in good shape, running her at 3000 won't hurt it a bit. It will get noisy and don't expect very good fuel mileage because your vehicle isn't aerodynamic. If you gear the thing to turn 2000 at 65, you won't have enough power to run it there except down hill.

I’m running 4.10 gears and 32.5” or so tires for very comfortable 50-55 mph and can go 60-65 if needed.

Many times it isn't the truck that limits top speed, but rather it's the driver. High speed runs in an AD truck is LOUD. Cab noise, shakes, rattles, etc.

Just make sure all is in GREAT working order before the attempt. Good brakes, steering, tires, wheel bearings and all. Failure at high speed can have very bad results.