What rear gear to run in a 1989 'Maro?
05-17-2010, 01:40 AM
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Car: 1989 Camaro RS
Engine: Chevy 353 (5.7 350 bored .020)
Transmission: Turbo 400
Axle/Gears: Not sure yet. Looking at a 3.42
What rear gear to run in a 1989 'Maro?
Hello, it's Rob. I am trying to figure out what rear gear to run in my Camaro. I think I've decided to go with a 700r4 for overdrive along with several other reasons. First I decided to go with a Powerglide and put well over $600 dollars into it then figured that wasn't going to work. Then I had, and still do have, a TH-400 laying around, I don't like that now. So I think the 700r4 is going to be what I go with. I should have done my research before...
I found a thing on the internet called starting gear ratio. How important is it with automatic transmissions? With the 700r4's 3.06 starting gear and a 3.42 rear gear that would keep my starting line ratio at 10.46. "A 9-10-11 SLR is desireable."
Would I benefit with the 3.42 or would a 3.70, 3.73, 3.90, 4.10 be better? It is a 8.5" 72 Cutlass rear end. I'm looking for a very hard launch.
Some help would be appreciated, thanks, Rob.
I found a thing on the internet called starting gear ratio. How important is it with automatic transmissions? With the 700r4's 3.06 starting gear and a 3.42 rear gear that would keep my starting line ratio at 10.46. "A 9-10-11 SLR is desireable."
Would I benefit with the 3.42 or would a 3.70, 3.73, 3.90, 4.10 be better? It is a 8.5" 72 Cutlass rear end. I'm looking for a very hard launch.
Some help would be appreciated, thanks, Rob.
05-17-2010, 01:48 AM
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Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: What rear gear to run in a 1989 'Maro?
Hello, it's Rob. I am trying to figure out what rear gear to run in my Camaro. I think I've decided to go with a 700r4 for overdrive along with several other reasons. First I decided to go with a Powerglide and put well over $600 dollars into it then figured that wasn't going to work. Then I had, and still do have, a TH-400 laying around, I don't like that now. So I think the 700r4 is going to be what I go with. I should have done my research before...
I found a thing on the internet called starting gear ratio. How important is it with automatic transmissions? With the 700r4's 3.06 starting gear and a 3.42 rear gear that would keep my starting line ratio at 10.46. "A 9-10-11 SLR is desireable."
Would I benefit with the 3.42 or would a 3.70, 3.73, 3.90, 4.10 be better? It is a 8.5" 72 Cutlass rear end. I'm looking for a very hard launch.
Some help would be appreciated, thanks, Rob.
I found a thing on the internet called starting gear ratio. How important is it with automatic transmissions? With the 700r4's 3.06 starting gear and a 3.42 rear gear that would keep my starting line ratio at 10.46. "A 9-10-11 SLR is desireable."
Would I benefit with the 3.42 or would a 3.70, 3.73, 3.90, 4.10 be better? It is a 8.5" 72 Cutlass rear end. I'm looking for a very hard launch.
Some help would be appreciated, thanks, Rob.
well the way I see it.... a 3.42 is good for highway speeds... it will keep your RPM within good RPMs... 3.73 gears, you may hear the roar of the raw power that's pushing your anchor... well anyways... what I would recommend is 3.42 for 305-350 stock... 3.42-3.73 for 383 and up... that's just my bucket of pennies...
05-17-2010, 02:18 AM
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Car: '91 RS, '72 Pro/Street Z28
Engine: 305 TBI, Blown 468ci w/NOS
Transmission: 5 Spd, 2 Spd Powerglide
Axle/Gears: 3.08, 4.88
Re: What rear gear to run in a 1989 'Maro?
What are your plans for the car? As in, do you plan on racing it, or is it strictly going to be a DD with the occasional trip to the track? Also what size tire height are you running out back?
With a 700r4 you have that extra OD gear, so running 3.73's aren't really going to kill your mpg as much as the TH400 would. If you do a lot of freeway driving, I'd probably go with the 3.42's. Now, 4.10's on the other hand will definitely give you the best "hard launch" you want.
I think it really boils down to what direction you want to go with the car. (I suggest forward....really fast!!!) J/K
With a 700r4 you have that extra OD gear, so running 3.73's aren't really going to kill your mpg as much as the TH400 would. If you do a lot of freeway driving, I'd probably go with the 3.42's. Now, 4.10's on the other hand will definitely give you the best "hard launch" you want.
I think it really boils down to what direction you want to go with the car. (I suggest forward....really fast!!!) J/K
05-21-2010, 03:22 AM
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Car: 1989 Camaro RS
Engine: Chevy 353 (5.7 350 bored .020)
Transmission: Turbo 400
Axle/Gears: Not sure yet. Looking at a 3.42
Re: What rear gear to run in a 1989 'Maro?
It will mainly be a drag car, 70/30. I'm building a 350 for it, hoping for about 400-450 horsepower. I did a lot of work to the heads so I should be around my estimate. I'm not sure on the tire size yet. I'm looking to find the biggest rear tire I can run on the car. The rear end sticks out 1/2 an inch on each side because it is a 1972 Cutlass 8.5. So any help with that would be a big help.
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