Big tire guys what gear ratio are you running?

Mark Demko · Jul 25, 2022

sean Buick 76 said: ↑

If I ever do it again I will use a gm 6 speed auto, but yes so far the 200 has been great. It was about $4000. There is nothing better than being able to shift into overdrive on the highway, highly recommended. Art car has been building 1000 Hp 200s for a long time. Lots of GN guys going fast with the 200 as well. My car is under 3000 pounds so that helps too.
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Does the six speed auto have deeper lower gear ratios and similar overdrive ratios as a 4 speed auto or are their just two more over drive ratios available?

mbryson · Jul 25, 2022

https://www.atiracing.com/products/trans/6L80E8L90E/index.htm#:~:text=The 6L80E has a gear,67.

6L80E 6-Speed Transmssion
The 6L80E has a gear ratio spread of 4.03, 2.36, 1.53, 1.15, .85 and .67. At 500HP, the clutches in these units go out and at 700HP you WILL start hurting hard parts. ATI can build up your 6L80E transmission for up to 1000HP. 8L90E 8-Speed Transmssion
The 8L90E is an eight speed with gear ratios of 4.56, 2.97, 2.08, 1.69, 1.27, 1.00, 0.85, 0.65 and REVERSE 3.82. A numerically high 4.56 first gear ratio offers strong take-off performance while a wide 7.0:1 overall ratio helps optimize cruising efficiency. Two versions are available: a slip-yoke design for use with the LT1 engine and a fixed-yoke design to be used with the LT4. ATI upgrades all 8L90E transmissions with increased clutches and a different clutch material make-up and also upgrades the clutch drums from LT1 units. These units are a great choice for everything from a '32 Ford Street Rod to a '69 Camaro Pro touring car to your drag car like those seen on Drag Week
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200r4

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Transmission & Drivetrain

GEARSTAR PERFORMANCE in Transmission & Drivetrain

200-4R Transmission: The Holy Grail of Power, Fuel Efficiency

If you are looking for a way to upgrade your classic muscle car’s Powerglide or TH350, then you would be hard-pressed to find a better answer than the 700R4, or the 200-4R. Yet while the 700R4 is often seen as the more popular successor to the throne of the TH350, the 700R4 is not going to squeeze into every build, not is it necessarily the best fit for your car – especially if you are going forward with a lot of aftermarket work in mind.

If you are looking for an upgrade to your old muscle car and want something that both packs a punch and substantially improves your fuel efficiency, then the 200-4R is the right place to start. Its bellhousing, drive shaft, and mechanical speedometer make it a superior fit for vintage cars, and its sturdier build and better torque capacity make it the better non-electronic 4-speed overdrive transmission for classic GM performance builds.

It is not very costly, can still be found scrap/salvage yards and in junk shops, and is reasonably affordable. And remember, if you snag yourself a late-model 200-4R from one of the more recent productions, it will handily outdo the stock 700R4 found in older vehicles.

It is by no means a perfect transmission and the 700R4 will typically outdo it, and even if you pick up a newer stock version from the wrecking yard at a bargain you will still have some ways to go to making it race-worthy, but a little magic and some elbow grease will turn the 200-4R into your personal holy grail of power and fuel efficiency.

History of the GM 200-4R Transmission
The 200-4R was a continuation of the Turbo Hydramatic line of GM transmissions, specifically being the successor of the TH200, a light-duty TH350 designed to improve fuel efficiency in the face of the oil embargo of 1973.

Years later, in 1981, the TH200 was replaced by the newly-introduced 200-4R, a 4-speed automatic overdrive transmission used in high-power GM trucks and cars, including the Buick Grand National and Pontiac Firebird Trans-Am. The 200-4R can be found in various GM B-body vehicles, C-body vehicles, G-body vehicles, and D-body vehicles.

Similar in build to the TH350, the 200-4R proved to be a great update to the outdated 3-speed transmission in builds where an overdrive gear was a must. Eventually, in 1990, the 200-4R was phased out for the 700R4, and later iterations of the same transmission including the 4L60 and 4L60-E.

Rundown on the Numbers
The 200-4R is a 4-speed automatic overdrive transmission by GM, capable of fitting into most Chevy’s from the 80s and before, built similarly to the TH200 and TH350, as well as the 2-speed Powerglide transmission. Build with a torque converter lock, a 27-spline input/output shaft, 11-quart fuel capacity, a case length of about 27” and a width of about 19”, and an aluminum outer casing, its torque capacity outdoes even the reliable 700R4 of the time. Its gear ratios are:

1st gear: 2.74

2nd gear: 1.57

3rd gear: 1

4th gear: .67

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So 6L80
4.03
2.36
1.53
1.15
.85
.67

Vs 200

1st gear: 2.74

2nd gear: 1.57

3rd gear: 1

4th gear: .67

6l80, I could run a 3.55 gear (or almost whatever you would want). I believe I had a 6L80 in my 2009 G8. It had 360 HP and felt like a lot more. The 4.03 first makes some sense now. I think those cars came with a 2.92 rear (?) and a common swap was moving to the Camaro 3.42 rear

sean Buick 76 · Jul 25, 2022

mbryson said: ↑

6l80, I could run a 3.55 gear (or almost whatever you would want). I believe I had a 6L80 in my 2009 G8. It had 360 HP and felt like a lot more. The 4.03 first makes some sense now. I think those cars came with a 2.92 rear (?) and a common swap was moving to the Camaro 3.42 rear
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Yes the 6 speed is amazing! Highly recommended. My tow rig has a modified 6.0 with the 6 speed and it’s great. My neighbor runs 1000 wheel Hp with a stock 6 speed and a triple disk converter.

unlike all the 4L60E, 80E, etc the 6 speed trans is very beefy and can handle big power from factory. It’s a bit larger and heavier but I feel it’s worth it.

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Big tire guys what gear ratio are you running?

Mark Demko Well-Known Member

mbryson Owner of Ornery grandma Buick

sean Buick 76 Buick Nut

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