what is good set cruise gears

-
Look at some of the online caculators, you have to input tire size etc to get an accurate reading.
 
It depends what you are trying to do. Then you have other factors, such as cam,convertor,etc....glad you asked.
 
X2 It depends on what you want to do with the car.

What size tires and rims are you using? (this affects the revs per mile). What is your target "cruise" rpm?
 
What gears do you have now and what rpm does it cruise at ?
Are you looking for lower rpm at hyw speed or more acceleration ?
 
duster rege said:
1975 318 mild cam 4 barel headers runs great 8 1/4 rear end seems like need another gear whats a good ratio
Click to expand...

whats in it now??


not gonna get much better highway cruiser then a 2.45..

2.94 is a nice all around gear in my opinion.

3.23 is decent also..
 
In the 8 3/4"'Chrysler speak, the 3:23 is considered their "maximum performance" ratio....so something around that!
 
Go with 3.23 - 3.55. I have a Barracuda with 3.91's and it winds too high on the highway. 4000 RPM at 70 MPH!

Go with 3.23 if it's a daily driver. 3.55 if you would rather get more off the line and give up some MPG.
 
Automatic or four speed? With a four speed, you can go 3.55 easy. I have them and love them. Great gear for cruising.

With an automatic, I'd run 3.23s to account for the slip in the converter.
 
Oldmanmopar said:
8 1/4 would be 321's
Click to expand...

I considered mentioning that. The difference doesn't mean much unless you go hunting 323 gears that will fit the 8.25 housing. 321 is correct.
323 is found in 8.75 housings.
 
my vote is 4.11 rear gear with a 27" tire and 4500 stall. put a big block thats ready to run in front of all that and all your problems are solved. lol
 
Can somebody here tell me why 8 1/4 rear ends have two difference ring sizes????

Thanks...................................... PETE..........................
 
Oldmanmopar said:
8 1/4 would be 321's
Click to expand...

In stock form, that's correct. And most companies only make replacement gears for that rear end.

I believe US Gear makes 3.23 gears for the 8-1/4" but I could be wrong. I haven't looked for anything less than 3.55:1 in a while.

Good catch though.
 
krazykuda said:
Go with 3.23 - 3.55. I have a Barracuda with 3.91's and it winds too high on the highway. 4000 RPM at 70 MPH!

Go with 3.23 if it's a daily driver. 3.55 if you would rather get more off the line and give up some MPG.
Click to expand...

Just how much MPG can one expect from being at 3:55 vs the 3:21 for a mild 318 auto, 26" tires 90% driving in town under 40 mph?
 
duster rege said:
tag on cover says 271 running 14 inch tires thanx 4 input guys fabo has helped me numerous times
Click to expand...

It's not the rim size but the total diameter of the tire that matters. I'm guessing they are probably a stockish tire, so something like a 25 or 26" diameter. I like the 3.55 gears myself but with a taller tire. So my vote is the 3.21s as you have it now. It will wake it up quite a bit.
 
Dodge74 said:
Can somebody here tell me why 8 1/4 rear ends have two difference ring sizes????

Thanks...................................... PETE..........................
Click to expand...

Because the trucks had what was an 8 3/8 rear axle. Same housing and a lot of the same internal parts. People sorta just lump them all together.
 
Dodge74 said:
Can somebody here tell me why 8 1/4 rear ends have two difference ring sizes????

Thanks...................................... PETE..........................
Click to expand...

The weird ring sizes are due to the pinion gear requirement. The 2.45:1 and 2.21:1 gears required more offset than the original carrier could handle. Hence the reason that the carrier for these gears won't handle the 2.7:1 (and >) gear sets.
 
You must log in or register to reply here.
-

Back
Top