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View Full Version : About to get Eaton swapped... 3.55 or 4.10 gears?



z man
01-11-2020, 10:57 AM
My 26K mile '04 is currently at Mo's for an Eaton swap and a few other things (I am beyond excited to say the least). HOWEVER, I am having a difficult time coming to a decision on rear gears... stick with the 3.55s or go with 4.10s? Car will be a weekend cruiser with some spirited driving, including some on the highway. It WILL NOT be taken to the track. I have stock wheels and tire size (Cooper Zeon RS3G1s). Marty and Jeff recommend the 4.10s, which I will likely go with. My only concern is traction and "losing" 1st gear drive-ability with stock wheel width and tires. I've already scoured the site and spent many hours reading about the different set-ups out there... all the way back to BillyGman and his Trilogy with 4.56 gears, 3K stall, and DRs. Some members have said they initially went with 4.10s N/A then S/C'd later on.... but also said if they had S/C'd first they would have likely stuck with 3.55s. Maybe I should stick with 3.55s and drive it for a while?

Can any of you Eaton swapped or Trilogy guys offer some insight? Thanks

RubberCtyRauder
01-11-2020, 11:18 AM
You just need throttle control with boost and 4.10..if you mash the gas, then traction can come an issue. I have 495 Rwhp and 4.10

sailsmen
01-11-2020, 11:28 AM
The Throttle is controlled by you!

If you feel you cannot control the throttle then put on a throttle stop.

Below 40mph with the stock rear tires I never floor because it's faster not to.

Black Terror
01-11-2020, 12:38 PM
I found that drivability around town was much better with the 3:55 than 4:10 on a Trilogy Marauder(480RWHP). Switching back to stock gears was the best thing I did after Trilogy installation until I did Zack's Big Brake Kit. Together, they are awesome.

Mr. Man
01-11-2020, 01:01 PM
Split the difference, and try 3.73's

justbob
01-11-2020, 02:42 PM
4.10 or even 4.30. Certainly no less, that would just be silly. [emoji6]


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martyo
01-11-2020, 02:51 PM
4.10 and don’t look back.

mm svt
01-11-2020, 02:54 PM
If Marty and Jeff suggests 4:10, why ask here you have the information you need.


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Bigslim1
01-11-2020, 03:49 PM
With the bottom end torque that the Eaton blower has the 3:55 would be fine. If anything the 3:73's would be more than you would need.

musclemerc
01-11-2020, 03:51 PM
4:10's @13psi was a lot of fun
4:10's @ 20psi not so much

decipha
01-11-2020, 04:37 PM
if its not a race car and is really a weekend spirited cruiser that never goes to the track, I would recommend the same as I do for a highway cruiser

4k stall and 3.27s

z man
01-11-2020, 08:05 PM
If Marty and Jeff suggests 4:10, why ask here you have the information you need.


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I suppose because I tend to over-research and over-analyze things. Since I've never driven a S/C'd Marauder, I was hesitant to do the gears at the same time as the blower... thought maybe I should drive it S/C'd with 3.55 gears for a while then decide. I talked to Marty the other day and was dead set on 4.10s, but then started looking through old threads again and began to question my decision... started thinking about things like not having widened wheels, etc.

Peace2Peep
01-11-2020, 08:24 PM
I've got 4.10's and widened wheels and an Eaton (Thanks Curless!) and I LOVE IT! You will enjoy it...either way, but I like the immediate response. I'm never going to drag race, I want to pull away at lights and on/off ramps.

justbob
01-11-2020, 09:26 PM
Just a few short years ago nearly every answer would have been to keep the 3.55’s. Funny how times change.

The very first decent mod to my car was a Trilogy. The night I got it done I took it out with another Trilogy owner riding shotgun and after the first time I laid into my comment was “That’s it???”. I guess I was expecting a whole lot more after the years I spent drooling over it? A retune and a set of 4.30’s (thankfully not heeding anyone’s advice from here) and I was MUCH happier. For a few years. [emoji16]


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Shinker
01-12-2020, 08:15 AM
I suppose because I tend to over-research and over-analyze things. Since I've never driven a S/C'd Marauder, I was hesitant to do the gears at the same time as the blower... thought maybe I should drive it S/C'd with 3.55 gears for a while then decide. I talked to Marty the other day and was dead set on 4.10s, but then started looking through old threads again and began to question my decision... started thinking about things like not having widened wheels, etc.
I had my mind made up I was gonna buy 31 spline axles, Detroit truetrac and swap the old ring and pinion over to save a few bucks but now I’m second guessing too. No way I’ll be at 20psi Not even sure I’ll hit 13psi cause 93 octane is best I can get around here. This is a great forum with so many knowledgeable members who have done all this stuff before but every time I check in here I find out I have to spend more money

Curless
01-13-2020, 07:15 AM
4.10's and don't look back! It only costs about 1 mpg and the grin factor is ridiculous! Stock car, the difference from 3.55 to 4.10 is .6 in the quarter mile or 6 car lengths!!!