The Stovebolt Site Forums The Shop Area Engine Shop 54 chevy with Hydramatic tranny

I am purchasing a 54 1/2 ton that has the Hydramatic tranny Would like to keep it as original as possiable but would like to be able to drive on the highway at a decent speed. Thought I would see if anyone could give some good ideas on how to best accomplish this.
Thanks from a old new guy

If you want to keep the engine and tranny original, try a 3:55 ring and pinion gear set from Patrick's. However, you need to get a rear end from a 47 through 53 AD to accomplish this as the 3:90 rear end in the 54s won't accept the new gears.

chevllssc,

What is a decent speed? I am able to run smoothly and safely between 55-65 mph in my '54 trucks (including a Hydra-Matic). Been doing this for many years. It's nice to have good tires and a tight front suspension, but that would still be the case with a lower ratio (higher speed) rear end.

Tim

Thanks Tim your the person I was hopeing to hear from. Been checking out your site very nice. Once I get the pick-up back (I owned it one time before)long story. I will probably need a lot of advice from you.

Thanks
(Cliff)
chevllssc

chevllssc,

Greg_H is in Enid, OK. He knows a lot about the '54 Hydra-Matic Chevrolets.

I'll start working on mine when the garage warms up - next month, I hope. I drove it from NJ to my garage in Dec and it's been hibernating. Most likely we'll be regularly comparing notes/experiences.

Good luck,
Tim

Is it really worth the cost, work, trouble to change from 3.90 to 3.55? That's a 9% reduction in engine RPM for any given MPH. Will that really make an appreciable difference in fuel economy, etc.?

chevll - I recently switched the rear in my 54 from the original 3.90 to 3.55. (3 speed tran) i have not been able to drive it very far becasue i have some brake issues to deal with but Frank50 makes a good point. you will not see a tremendous amount of difference in anything by going from 3.9 to 3.55. i was fortunate that i was able to purchase a rear that already had everything rebuilt in it with the 3.55 pinion and for a very reasonable price. basically all i had to do was slide one out and slide one in. it all depends on what you want to do with your truck. if you are out there cruising and in fast traffic all the time then, in my opinion, you are much better off ditching the torque tube and spending your money on the blazer or s10 set ups that everyone is using. If you want a little driver to mess around town in and for short trips in no hurry then the torque tube is just fine.

I do not know about putting a Patrick's 3.55 kit into a '54 rear end, but an earlier rear end would not work with a '54 Hydra-Matic transmission, without shortening the drive-shaft and torque-tube.

Maybe the '54 Hydra-Matic torque-tube and driveshaft could be used on the earlier 1/2 ton rear end?

I agree with djed50 - just drive it. This combination of rear end (4-speed automatic) and torque-tube rearend is uncommon - a good conversation piece and not a bad ride.

Ok, you guys have convinced me if I do buy it back which I probably will I will leave it as is. I want to keep it as original as possible but I have gotten old, fat and lazy and want some comforts also.
Thanks for all the good information.