Diff gear ratios

[missallpc]

I have a 1957 3100 SB/SS with a 235 and a 3 speed. I finally got the truck well enough to drive it around the neighborhood. When I'm running at about 40 mph the engine sounds like it's ready to come unglued. Can some one tell me what rear gear ratios are available for this truck and are there any problems associated with this.

thanks ....Paul

[magicoolbus]

Hi Paul,
First, welcome to the board! Mine has a 3.90 in it. There are others that were optioned I am sure, the only way to find out for sure is to take off the cover and see. Never hurts to change out the gear oil.
A very good swap is to put in the 3.38 R.P. kits. Patricks sells them as complete or builder kits. I got mine off of E-bay. Still waiting to put it in, going to swap in a T-5 and the 3.38 for a highway cruising machine.
JB
http://www.patricksantiquecars.com/chevy_parts.html

[missallpc]

JB, Thanks for the info....Paul

[OrrieG]

The link in my signature will drop you onto a spec manual for TF page. Scroll down to year index and click yours. Then click contents and look for rearend information. It will show all the available ratios for each model. Keep the link lots of good info in the book.

[agnes the dog]

Originally Posted by magicoolbus

Hi Paul,
First, welcome to the board! Mine has a 3.90 in it. There are others that were optioned I am sure, the only way to find out for sure is to take off the cover and see. Never hurts to change out the gear oil.
A very good swap is to put in the 3.38 R.P. kits. Patricks sells them as complete or builder kits. I got mine off of E-bay. Still waiting to put it in, going to swap in a T-5 and the 3.38 for a highway cruising machine.
JB
http://www.patricksantiquecars.com/chevy_parts.html

JB - I did a T5 swap a couple years back with my 4.10 and it was perfect! I recently swapped the rear to a 3.73. It's great for around town and it really helped the 1st - 4th ratios, but I'm a little disappointed in the 5th ratio. I'm running a 305 with 275-ish hp. Fifth gear is really not usable until 65-70mph. I would have been really disappointed if I had tried a 3.38 with the T5. I would suggest that you to try your 3.38 gears before doing the T5 swap. You might find that the 3.38 is plenty for your current transmission set up. It might save you time, effort, and a few bucks! :-)

[57chevyman]

im in the same boat... 3 speed with 4.11 rear end. engine is screaming at 50mph. if i drive down the local highway to the car show ten min down the road, i speed up to about 50mph and then step on the clutch and coast for a while to give the engine a break.

i dont mean to hijack the thread, but can i keep my rear end, and step up to a five speed manual trans to be able to cruise on highway at a comfortable rpm? or do i really need to change both the rear end and transmission?

[Rickysnickers]

You would most likely be fine. All you would need is to the final ratio on the 5 speed trans, your overall tire height, and if you know the rearend ratio, it won't be hard to figure out the rpm you'd be cruising at at 60mph.

[twinsemi]

How tall are your tires. My 3.90 does OK on the fwy with 255/70-15's and no OD. They are 29 inches tall.