Rear Gear for Eaton Swap - 2003-04 Mach 1 Registry Owners Club

Pcmoore85 · 02-23-2013, 04:45 PM

I was wondering what is a good rear end gear ratio for a Mach 1 eaton swap car with the factory 3650 trans right now i have a 4.10 and am getting ready to do a eaton swap and I am nervous about my gearing being too low and going to make 1-3 gears pointless since the 3650 is lower geared than the t56 anyways and now with the eaton all the torque is going to be way lower rpm range

machgsxr · 02-23-2013, 05:34 PM

For street i would go 3.55 or 3.73.

For track what size tires do you use. 28" 4.10s are fine. 26" 3.73s or 3.55s.

Bmeagher · 02-23-2013, 05:48 PM

Leave the 4.10's in for now. What are you doing with the car? DD, Drag racing?
If your stock heads/cams/exhaust, you'll only be about 420-450rwhp. 4.10's would make it wicked fun!

Stopsign32v · 02-23-2013, 06:49 PM

4.10s in an Eaton swapped Mach would be faster than 3.55s or 3.73s.

CHicks26 · 02-23-2013, 09:36 PM

If you are gonna use a bias ply tire leave the 4.10 and use 26" tire for the track. They grow as you get down the track. I have 4.30's in my car and i was gonna do an eaton swap and leave the 4.30's and use a 26" bias ply because they grow the faster you go like a slick basically. I was gonna use them at least until it proves me otherwise that it wont work lol

Stopsign32v · 02-23-2013, 10:24 PM

4.30s would be ideal unless you plan to trap more than 125mph in the 1/4. I think 4.10s would be the best choice.

Pcmoore85 · 02-24-2013, 07:36 AM

Thanks for all the replies I'm basically just going to have a street car maybe to the track every now and again I was just worried with the 4.1 having a problem with just blowing the tires off if I jumped on the gas pedal

Stopsign32v · 02-24-2013, 08:51 AM

Quote:

Originally Posted by Pcmoore85

Thanks for all the replies I'm basically just going to have a street car maybe to the track every now and again I was just worried with the 4.1 having a problem with just blowing the tires off if I jumped on the gas pedal

Unless you have some good tires that is very possible

SHAKN' 04 · 02-24-2013, 09:46 AM

Go with 3.55s, all around great gear for hwy and track. That's what I'm running

02-23-2013, 04:45 PM	#1
Pcmoore85 Registered User Join Date: Feb 2013 Location: Mooresville Posts: 21	Rear Gear for Eaton Swap I was wondering what is a good rear end gear ratio for a Mach 1 eaton swap car with the factory 3650 trans right now i have a 4.10 and am getting ready to do a eaton swap and I am nervous about my gearing being too low and going to make 1-3 gears pointless since the 3650 is lower geared than the t56 anyways and now with the eaton all the torque is going to be way lower rpm range

02-23-2013, 05:34 PM	#2
machgsxr Registered User Join Date: Feb 2005 Location: San Antonio Posts: 6,414	Re: Rear Gear for Eaton Swap For street i would go 3.55 or 3.73. For track what size tires do you use. 28" 4.10s are fine. 26" 3.73s or 3.55s.

02-23-2013, 05:48 PM	#3
Bmeagher Registered User Join Date: Feb 2008 Location: Cowtown, Alberta Posts: 1,261	Re: Rear Gear for Eaton Swap Leave the 4.10's in for now. What are you doing with the car? DD, Drag racing? If your stock heads/cams/exhaust, you'll only be about 420-450rwhp. 4.10's would make it wicked fun! __________________ Maximum Motorsports race series shocks/struts, coilovers front and rear, K member, bump steer kit, solid steering shaft, Panhard bar. Built Rear End with 4.30's, Hooker longtubes, Comp 106100's, Fidanza Aluminum Flywheel, Centerforce DF, *FR500 intaked 1/2" Spacer, Livernois Springs, Ford GT Followers in the works.* *SAE 378RWHP ,302 ft/lbs* 70-120mph run http://www.youtube.com/watch?v=1hqjiOeYWAE

02-23-2013, 06:49 PM	#4
Stopsign32v Registered User Join Date: Nov 2007 Location: Greenville, SC Posts: 2,554	Re: Rear Gear for Eaton Swap 4.10s in an Eaton swapped Mach would be faster than 3.55s or 3.73s. __________________ 03 white Mach1 JLT RAI \| 1/2 spacer \| Catback \| 4.56s 7.76@87.8mph

02-23-2013, 09:36 PM	#5
CHicks26 Registered User Join Date: Aug 2011 Location: Tuskegee, AL Posts: 402	Re: Rear Gear for Eaton Swap If you are gonna use a bias ply tire leave the 4.10 and use 26" tire for the track. They grow as you get down the track. I have 4.30's in my car and i was gonna do an eaton swap and leave the 4.30's and use a 26" bias ply because they grow the faster you go like a slick basically. I was gonna use them at least until it proves me otherwise that it wont work lol

02-23-2013, 10:24 PM	#6
Stopsign32v Registered User Join Date: Nov 2007 Location: Greenville, SC Posts: 2,554	Re: Rear Gear for Eaton Swap 4.30s would be ideal unless you plan to trap more than 125mph in the 1/4. I think 4.10s would be the best choice. __________________ 03 white Mach1 JLT RAI \| 1/2 spacer \| Catback \| 4.56s 7.76@87.8mph

02-24-2013, 07:36 AM	#7
Pcmoore85 Registered User Join Date: Feb 2013 Location: Mooresville Posts: 21	Re: Rear Gear for Eaton Swap Thanks for all the replies I'm basically just going to have a street car maybe to the track every now and again I was just worried with the 4.1 having a problem with just blowing the tires off if I jumped on the gas pedal

02-24-2013, 09:46 AM	#9
SHAKN' 04 Registered User Join Date: Jan 2008 Location: Kyle, Texas Posts: 2,285	Re: Rear Gear for Eaton Swap Go with 3.55s, all around great gear for hwy and track. That's what I'm running __________________ SOLD04' Mach 1 -Comp Cams 106100's (deg 106/110) -Eatonswap with 3.4 Pulley -Full Exhaust (mac lts & xpipe, sss terminator c/b) -Built Rear w/ 3.55 gears [B]-Tuned by Lethal Performance of San Antonio -510hp/478tq

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