The Stovebolt Site Forums The Shop Area Engine Shop wanting to change rear end ratio on 1954 3100

I've considered changing the rear end ratio on my 54 chevy 3100. not sure but i think it has the 3.90 in it now. it still has the closed driveshaft. several venders sell the 3.55 gears. They state you can cruise a little faster and also have lower RPM's. I don't care about the faster speed but would like the lower RPM's. I also have the 3 on the tree tranny.
Will it rob me of any power at take off or anywhere along the line. Just trying to figure out if it is worth the trouble.

I love this truck.

There is no free lunch. The reduction in torque (overall gear multiplication) is exactly the same as the change in RPM. Engine RPM drops by 9%, torque exactly the same, speed in MPH in each gear is up by 10% (what used to be 50 is now 55). That's a pretty big change, and you'll feel the difference.
What you really need is an overdrive to both keep a big 1st gear for traffic, and slow the engine down when cruising.

ok i've read a little about the overdrive. were would i look for an overdrive?

Nothing is simple there either. Chev offered a SM318 with a Warner OD, but that requires an open drive shaft which means getting a 55 or newer third member. And of course you will have to have a relay to operate the OD. Chev overdrives appear on eBay occasionally. I prefer overdrive transmissions and have been using them for 45 years. You can lock the overdrive out and have the pep around town of direct, but then when you get on the highway you can let the overdrive kick in and get a 30% reduction in RPM.

I think I will just be happy with the way it is.