The Stovebolt Site Forums The Shop Area Engine Shop rear end gears

what can i expect in mph boost by putting a rear end kit(ring and pinion) in my 54 chevy pu provided i keep the stock tranny, torque tube etc.

If all else is unchangedss, you should be able to calculate a new speed at a given engine RPM fairly simply:

take the current ratio (eg 4.10), and divide by the new ratio (eg 3.73). The result multiplied by your current speed at a given RPM (eg 50 mph @ 2700) will give you the new speed.

4.10/3.73=1.099

1.099*50=55 mph @ 2700.

This doesn't guarantee that your engine will be able to turn 2700 with the new rear, but it is a simple conversion for the numbers.

I did it to my '50 recently and notice that I'm now shifting from 3rd to 4th around 7-8 mph faster and I've been caught traveling down the highway between 60-65 whereas it use to be around 55 max.

This is all based upon just listening to the engine at shift points and when I feel I am reaching top speed.

Though it's a LOT of work, it's great to have that extra speed available.

You can go to www.ring-pinion.com/calculators/calculatorsind.html and play with calculators there. You can educate yourself fully on how tire size, rear end ratio, and throwing an overdrive tranny into the mix effects your top end speed and fuel economy.

Well, first of all. 54 half tonners have 3.90 not 4.10. So the difference will be not as great as with the earlier years.
Secondly, call Patrick's there is a small part you need from an earlier torque tube for your 54 unit to accept the kit. I forgot the name of the part. Something like muffler bearing...

How hard is it to replace the ring and pinion in a '54 Chevy 3100? Mine are shot and the mechanic said I would be better off finding a used pumpkin/drive shaft.

Thanks,
Bill Yates
Austin, TX

thanks for the info and wb sites. don't know if i want to pay 500 for 10 mph but really hate to sub because everything is working pretty good right now. read in another post that 85 blazer rearend will go under there without too many mods??? of course i would have to change torque tube and tranny. guess i will just "stay to the right" untill something breaks. i have a 74 chevy donor truck available but unfortunately nothing is an easy match up. thanks again for the excellent info. i am sure i will be back!!

I did some studying and went with 3.38 gears. Cleaned up everything myself then had the Gear Shop install the ring/pinion and set it up for me. They charged me 2 hours shop time. Got it all back in the truck (55.1 3100)this weekend. Those calculators will give you a good idea what to expect. I changed rear end and tire size (a little smaller) at the same time. The net gain at 55 mph was 2650 rpm to 2300 rpm and NO MORE singing rear end.
It sang until catastrophic failure, blow up, bang, crunch, instant lock up at 50 mph, HANG ON, BIG flat spots on the rear rubber.
Like the old saying.....
It ain't over til the fat rubbers sing
Fix it before it goes too far!!

Buddy in AK

Buddy, glad you and the truck made it through the trauma. how is you nose and the windshield :p
Did you get the vinyl on the seat replaced yet?

No nose to windshield action, still looking at seat cover replacement options and it does make one consider seatbelts/shoulderbelts.