3.55 rear gears...
Thread Starter
Racer
Joined: Nov 2003
Posts: 342
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From: Felton De
3.55 rear gears...
I'm thinking about putting 3.55 rear gears in my vette. The shop quoted me 500 for everthing from parts to installation. Is that a decent price?? Also, in your all's opinion, is a 3.55 the best replacement for my setup?? And what does it feel like after the swap, if any of you been there done thats wanna comment :auto: The setup: 71 L48 T-top with origonal factory 3spd (th350?). Bumped up to around 375-400hp. And i believe the factory 3.08? rear gears. Tks.
Brandon :flag
Brandon :flag
Intermediate
Joined: Mar 2003
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From: flomaton al
Re: 3.55 rear gears... (BrandonS)
The first step is determining what rear gears you have.
If you would like the car to reach it's torque band sooner a.k.a. be quicker choose a numerically higher rear gear, if you would like to increase you top speed and increase your gas mileage choose a numerically lower gear.
What I am trying to say is this, it is all personal preference. I had a turbo 400 in my 74 with 3.73 and I liked it, but I know a lot of guys on here would call me crazy. On the other hand my dad wanted me to go with 4.11.
It is also important to consider your future plans for the car if you are planning to go with a od tranny of some kind that should also influence your decision.
500 sounds very reasonable, if you are talking about a reputable shop, the lowest quote I have found was 750.
Finally, sorry so longwinded, just trying to help.
If you would like the car to reach it's torque band sooner a.k.a. be quicker choose a numerically higher rear gear, if you would like to increase you top speed and increase your gas mileage choose a numerically lower gear.
What I am trying to say is this, it is all personal preference. I had a turbo 400 in my 74 with 3.73 and I liked it, but I know a lot of guys on here would call me crazy. On the other hand my dad wanted me to go with 4.11.
It is also important to consider your future plans for the car if you are planning to go with a od tranny of some kind that should also influence your decision.
500 sounds very reasonable, if you are talking about a reputable shop, the lowest quote I have found was 750.
Finally, sorry so longwinded, just trying to help.
Thread Starter
Racer
Joined: Nov 2003
Posts: 342
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From: Felton De
Re: 3.55 rear gears... (BrandonS)
You longwindedness is very much appreciated :cheers: I'm pretty much aware of the effect of the gears, just not to what extent. As for longterm plans, i want a 700r4 to go in eventually, but it could be a year or two. With that in mind, i'm not sure if i want to go all the way to 3.73's or not. 3.55 just seems like the perfect blend of streetability and hardcore driving.... but i'm here for opinions! Tks
Brandon :flag
Brandon :flag
Drifting
Joined: Jan 2002
Posts: 1,500
Likes: 0
From: N.Y
Re: 3.55 rear gears... (blunsford)
Just did 3.70 gear swap last week I had 3.08 gears. Went from a 12.90 to a 12.50 in the quarter mile. Park way driving is ok............. I guess it keeps me from speeding. :auto:
Le Mans Master
Joined: Oct 2000
Posts: 6,209
Likes: 33
From: Texas-out west
Re: 3.55 rear gears... (BrandonS)
sounds like a decent price, keep old gears so you can go back if you want, i like 3.55s, have 3.70s and they are little busy for high speeds, had 3.55s and really preferred them. :D
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Re: 3.55 rear gears... (LT1driver)
:iagree: I too have 3.70s and wish I had 3.55 or even 3.36. Guess it depends on what you want to do with it. 3.7 is pretty much a max (with overdrive) IMHO for much interstate driving. Without overdrive I'd get a 3.36. If you want to drag race, then 3.55 or 3.73 is probably fine.
Drifting
Joined: Sep 2003
Posts: 1,325
Likes: 6
From: FRANKLIN GA
Re: 3.55 rear gears... (markdtn)
My 3.70's do fine with an overdrive on the interstate. I thought about the 3.55's, glad I got the 3.70's. If you ever decide to go with an overdrive trans. you'll be glad to have the 3.70's in it
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Safety Car
Joined: Aug 2000
Posts: 3,711
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From: San Antonio TX
Re: 3.55 rear gears... (BrandonS)
I went from 3.08 to 3.55 in my base-engined '72. Wonderful improvement. Not too much rpm on the road and a great improvement in torque multiplication around town.
The price quote is very reasonable. Don't forget to change the speedo driven gear. You should have a THM400, not a THM350.
My opinion is that the 3.55 is the best all-around street gear, not drag strip, but street. I use a 3.89 gear in my Fairlane and it's an ear full of rpm on the highway so, with that in mind, I usually stick to the side streets when cruising that one.
The price quote is very reasonable. Don't forget to change the speedo driven gear. You should have a THM400, not a THM350.
My opinion is that the 3.55 is the best all-around street gear, not drag strip, but street. I use a 3.89 gear in my Fairlane and it's an ear full of rpm on the highway so, with that in mind, I usually stick to the side streets when cruising that one.
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
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From: Clearwater FL
Re: 3.55 rear gears... (gerry72)
$500 is very cheap. Is he pulling the rear out of your car to? If he is I would be at his door ASAP. Is he putting in new gears, bearing, seals, races, clutch pack, fluid and additive. If he is than your getting a deal of a lifetime. He's pretty much doing all the work for just over $50 labor.
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Re: 3.55 rear gears... (BrandonS)
Go with a 200r4 and 3.70 gear. I have a 700r4 in my formula and with the low first gear it is a bit much off the line, smokes em easy as heck, but the 200r4 has a high first gear and better spacing between 1st and 2nd plus it is a direct bolt in for a th350. With the .6x overdrive the eng revs low on the e-way.
Melting Slicks
Joined: Aug 2003
Posts: 3,416
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From: dayton oh
Re: 3.55 rear gears... (BrandonS)
I went from the 2.87 to 3.55 & 700R4 at the same time !!!!
I read alot about the recommended ratios and arrived at the same conclusion you seem to have.
3.55 are a VERY good street combo
IMHO 3.70 would be overkill for street tires and a 375-400hp motor
Fevre is right about the 700R4 and 3.55's on the launch, that pavement BETTER be dry or it's donut time.
I read alot about the recommended ratios and arrived at the same conclusion you seem to have.
3.55 are a VERY good street combo
IMHO 3.70 would be overkill for street tires and a 375-400hp motor
Fevre is right about the 700R4 and 3.55's on the launch, that pavement BETTER be dry or it's donut time.
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Re: 3.55 rear gears... (Fast81)
Did I mention I am partial to the 3.7x gears, have a 3.70 in the vette and 3.73's in both the formula and highrider. :D In the formula I turn about 3k on the e-way at 80 mph while the highrider with it's larger tires turns about 2800, the vette turns 3500 with no OD and slightly smaller than stock tires.
Race Director
Joined: Jan 2003
Posts: 15,176
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From: State of Confusion
Re: 3.55 rear gears... (Fevre)
I had 3.73s installed in my '82 this past October; price break-down as-follows:
Gears: $135.00 (includes shipping)
Misc speedo-parts: $75.00 (drive gear, driven gear, sleeve)
Labor to swap ring & pinion, install speedo gears & sleeve, misc. parts & gear-lube: $350.00
TOTAL: less than $575.00. Installation was done by a buddy, with 30+ years of GM/Corvette-specific drive-train service.
As stated earlier by EDDIEJ82, I'm glad I went with 3.73s, as opposed to 3.55s; in-fact, with a .7:1 OD in the 700R4, 3.73s almost aren't ENOUGH gear!
I trapped @ 91 MPH, turning 'just' 4300 RPM in 3rd; I think 4.11s (or even 4.56s) would be better.
Still, the .73s are WAY better than the OEM 2.87s.....
Gears: $135.00 (includes shipping)
Misc speedo-parts: $75.00 (drive gear, driven gear, sleeve)
Labor to swap ring & pinion, install speedo gears & sleeve, misc. parts & gear-lube: $350.00
TOTAL: less than $575.00. Installation was done by a buddy, with 30+ years of GM/Corvette-specific drive-train service.
As stated earlier by EDDIEJ82, I'm glad I went with 3.73s, as opposed to 3.55s; in-fact, with a .7:1 OD in the 700R4, 3.73s almost aren't ENOUGH gear!
I trapped @ 91 MPH, turning 'just' 4300 RPM in 3rd; I think 4.11s (or even 4.56s) would be better.
Still, the .73s are WAY better than the OEM 2.87s.....
Safety Car
Joined: Aug 2001
Posts: 3,685
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From: Waterford Mi
Re: 3.55 rear gears... (Glensgages)
I put in 3.55's before I did the 200R4. Got about 11mpg on a road trip but was OK to drive. 3500rpm's @ 70mph. Now that I have the 200R4 she smokes-um-up without any trouble.
I kind of wish I could see what 3.70's would do :D
I kind of wish I could see what 3.70's would do :D
Race Director
Joined: Jan 2003
Posts: 15,176
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From: State of Confusion
Re: 3.55 rear gears... (redwingvette)
I put in 3.55's before I did the 200R4. Got about 11mpg on a road trip but was OK to drive. 3500rpm's @ 70mph. Now that I have the 200R4 she smokes-um-up without any trouble.
Before the gear-swap, I once got 23+ MPH, driving 75+ MPH, T-tops off, A/C blowing ice cubes, on a 230+ mile round-trip.
Since the swap, I averaged 17+ over 430+ miles, well-over 1/2 of it down two-lane roads, following the road-bed of the Pennsylvania Railroad, running the A/C again.
This summer, I hope to make a few dedicated MPG-runs, on the Interstate/Turnpike, hoping to exceed 20+ MPG.
70 MPH with the 700R4 is approx 2200-2300...
Racer
Joined: May 1999
Posts: 268
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From: CT
Re: 3.55 rear gears... (BrandonS)
I just recently made the switch from 3.08's to 3.55"s. It made a big difference in acceleration and in top end. A chart i looked at stated a 15% torque increase when going from 3.08 to 3.55's. Realistically you dont need to be able to do 160 anyway. With these gears im somwhere around 135 at redline when calculated. As for gas mielage "you shouldnt care when your in a corvette". Thats why i have my 1.4 litre datsun for my regular driver right now :lol: . My gas mileage i droped from 8 to 6 around town so it wasent like i was ruining a good thing. I definitely wouldnt go to 3.73's mainly because i drive the car alot and it is pretty high in the rpm's when cruising on the highway. If your going with the overdrive though mabey it wouldnt be as bad. Id find out the overdrive ratios and calculate what youll be running for rpm once you have the 700-r4 in.
Good luck
Kevin
Good luck
Kevin
