Gear for Eaton car

[xXAzureMach1Xx]

Alright, Got a full eaton swap and T56 in my mach 1. I have stock 3.55 gears. I picked up a set of track wheels, prolly end up bein the DD wheels also and found a GREAT deal on some new 275/60/15 MT. I know its a 28" tire and its goin to kill my gear. Im rebuilding the rearend and plan to run 3.73 with a 26'' tire, now with a 28'' tire im thinkin about 4.10s? The 4.10 should be about the same as 3.73 and 26'' tire. Is that about right? And how bad will the car be on the 315's dr on the street, Prolly will never see the 315 anymore but JW?

 

[mustang john]

Go with the 4.10s if your gonna use a 28" rear tire.

 

[xXAzureMach1Xx]

What about 3.90? I can get a good deal on some 4.10s tho so i may just do that.

 

[mustang john]

The 4.10s put me right at the top of 4th thru the traps about 6300rpms trapping 127-128in 4th. If your making less than 550rwhp then the 4.10s will be just right with a 28" tire. On the street i run 275/60/15 Nitto DRs (28") and its only 2300 rpms @ 70mph in 6th, perfectly acceptable in my book. As far as 3.90s i may have to go to them if i trap much higher but i dont have any experience with them but it seems that they would leave rpm on the table at the track, i guess it depends on what your focus is with the car.

 

[xXAzureMach1Xx]

Im making around 475ish and thats all the stock bottom end will hold. I dont plan to build the motor for about 3yrs unless it goes before then. I dont mind having to regear it later on either. just want something good for the setup now.

 

[mustang john]

Then the 4.10s and 28"s will be the ticket! I have a freind here in SA with an Eaton swapped Mach on the stock 5 speed and he made 455rwhp on 8psi with the stock pulleys and his car ran 11.3s if i remember correct, post some track #s when you get them!

 

[xXAzureMach1Xx]

Cool man thanks. Ill post the times when i go. It will be a few months tho.

 

[dntalman]

3.90 rear gear is the best for a Eaton car... If it is a 1/4 mile car.... If your goal is the short sprint 1/8... I liked the 4.30 gear

 

[xXAzureMach1Xx]

Yea i have been told that the 3.90 will do best with the 28'' tire. Think thats the way im goin.

 

[mustang john]

Yea i have been told that the 3.90 will do best with the 28'' tire. Think thats the way im goin.

What makes you think that? BADASS runs 4.10s with his 28"s and has for years, the fastest Eatons in the country run 4.10s. If you are setting up for the track anything less than a 4.10 gear with 28" tires will leave rpm on the table at the end of the run and leave potential ET on the table also.

If you cruise alot on the street then a gear ratio compromise is understandable, otherwise gear it so you get the full use of 4th on the big end.

Im not talking out of my ass here, i do have alittle experience with Eatons and drag racing myself.

 

[xXAzureMach1Xx]

What makes you think that? BADASS runs 4.10s with his 28"s and has for years, the fastest Eatons in the country run 4.10s. If you are setting up for the track anything less than a 4.10 gear with 28" tires will leave rpm on the table at the end of the run and leave potential ET on the table also.

If you cruise alot on the street then a gear ratio compromise is understandable, otherwise gear it so you get the full use of 4th on the big end.

Im not talking out of my ass here, i do have alittle experience with Eatons and drag racing myself.

Well I have posted a few other times and NO one seem to want to help with info on what gear would be best. I have only talked to one other guy and he said a 3.90 gear but he has a KB. I thought the 4.10 would do best because of what i have seen with people running a 26'' tire and 3.73 and the 4.10 is really close to the same setup as ther 3.37 and 26'' tire. I drive the car on the weekends but its no DD. Doesnt see much interstate speeds either so im not to worried with rpms at higher speeds. I want to set the car up for the 1/4 more then the street. Well you are just the person i need to hear from lol. Im goin for low 11's with the bulit rearend and the built T56. Think that could happen? The car is prolly makin 475ish is this cooler weather.

 

[mustang john]

Yeah you will hit your goal, maybe faster depending on your suspension setup and weight. If you have trouble finding info on the eaton seups then hit the terminator sections for sure even though you do have a mach the info is there for the eatons, maybe even try modularfords for more info. The drag race section is kinda dead here, everybody posts up in the section dealing with their model car and not their desired use of the car.

 

[Blk4V00GT]

I agree with John, if your maim goal is to set it up for the track then do it right the first time. Based on your current set up and 28in tires go straight to the 4.10s to get your best results.

You can't make more power for a while as your topped out on the stock internals, so make as much difference with the gearing and suspension as you can.

 

[BADASS03SVT]

4.10s all the way at that power and that tire.

with a heavy car, mild power and a good tire you want as much gear as possible. the difference between a 3.90 and a 4.10 isn't much...100-150rpms but you want 4.10s. see sig for the reason why...lol :beer:

 

[xXAzureMach1Xx]

Yea i have posted in the terminator section and got nothing. This was my last hope oke:. The car is pretty much full weight. Stock susp for now. Next thing on my list. 4.10s it is. Thanks :beer:

 

[Blk4V00GT]

Good luck getting the car set up, and good call on the gears.

 

[mustang john]

Yea im not the only voice in here anymore lol! Yup what these guys ^^^ said... and me too lol.

 

[BADASS03SVT]

Yea i have posted in the terminator section and got nothing. This was my last hope oke:. The car is pretty much full weight. Stock susp for now. Next thing on my list. 4.10s it is. Thanks :beer:

yea...full weight I would deff go 4.10s. the more gear to get that pig rolling the better :beer:

 

[xXAzureMach1Xx]

Thanks man:beer: