The TH350 can easily handle 600 lb/ft when properly built. It doesn't take anything super fancy. I have a couple at 600+ using a stock intermediate roller clutch setup. The int roller clutch setup is the common failure point of a TH350 when making HP, getting aggressive shifts, and burnouts.
Hate to break it to ya, but turbo 350s don't have an overdrive band. It wont shift past 3rd 'cause there isn't anything to shift to. You sure it's a TH-350? Make sure the cable that comes out of the tranny and hooks to the carb linkage (on the left side) is correctly hooked up and adjusted.
TH350 vs 700R4: Biggest differences
Shift control– The TH350 is controlled by engine vacuum and a kick down cable. The 700R4 on the other hand is controlled by a TV cable. The best way to think of the TV cable is as a throttle position sensor. The 700R4 uses an overdrive gear to reduce engine RPM at highway speed.With that being said, the TH350 is by far the best choice if transmission and engine combination plays an important role in your Chevy 350 transmission experience. The Turbo Hydra-matic 350 was first made to use in 1969 model cars.
The Turbo Hydra-matic 350 was first used in 1969 model cars. It was developed jointly by Buick and Chevrolet to replace the two-speed Super Turbine 300 and aluminum case Powerglide transmissions. The THM350 was also regarded as a 'three speed Powerglide' and during its development, was generally called this.
Only 7 left in stock - order soon. Bought this to replace the
TH350 in my 1972 GMC pickup. Shift quality is fantastic
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The TH-350 was a low-torque transmission that was used in heavy cars. With modification, the TH-350 could be used as a high-torque transmission in a light car. The TH-400 was a high-torque transmission that was used in heavy cars --- it was a much stronger transmission than the TH-350.
The TH400 was initially placed in Buick and Cadillac cars and later added to Chevrolet, Oldsmobile and Pontiac cars. This transmission eventually made its way into many of the truck applications for General Motors.
The TH400 is much stronger, but it doesn't have overdrive and the first gear is only 2.48:1. The 700R4 has an overdrive gear (0.7:1), and a 3.06:1 first gear, but it's not as strong. So it depends on what your using it for and how much power you have.
selling it as a good unit and with a "it will work" or your money back warrantee, it should be worth $150-200. There are many shops that sell a stock rebuilt TH400 for $600.
Turbo 400 Transmission (TH400) Specs. The Turbo 400 transmission was a 3 speed automatic transmission developed by General Motors. Overall the transmission remained in production an impressive 27 years before it was eventually replaced by a 4 speed electronically controlled transmission, the 4L80E, in 1991.
About 400-450 HP/TQ is the limit on the stock TH400. With ONE almost free modification and some minor valve body calibration changes, 800 HP on an otherwise stock TH400 is not a problem if it's assembled well (good endplay, etc), and the 34 element sprag is a wise addition above 450 HP or any drag usage.
Inside the 6L90 six-speed
The 6L90 is the strongest of GM's family of Hydra-Matic six-speed automatic transmissions.When the throttle linkage reaches a specific point, the cable triggers a mechanical detent valve inside the transmission--allowing it to shift into a lower gear. The Turbo 400 uses an electric switch to trigger a detent solenoid on the valve body to produce the same effect.
The TH400 is an automatic shift, three-speed, longitudinally positioned transmission. It is widely regarded to be a supremely durable and legendary transmission. The TH400 is conservatively rated at 450 ft. lbs. of input torque. Aftermarket building techniques take it well past that figure.
It shifts very firm under power. It barks the tires when shifting into reverse from park idling at 1200 rpm. When driving it will seek its way to high gear, and will not downshift by itself until the car is nearly stopped.
In OEM applications, a powerglide input shaft has a 17 count spline that engages the torque converter and two sealing rings midway down the shaft to complete the cooling circuit. The shaft also has a number of oiling holes throughout to complete the lubrication and hydraulics.
If you do change it you will need a new cross member and drive shaft as the 400 is shorter than the 700. the 700r4 has 180,000 miles on it and the turbo 400 is a brand new TCI super street fighter. Get a built 700r4 to handle your horsepower, the th400 will involve too many changes to make the swap economical.
The best cores for a 700R4 build were from 1987-92 they had all the factory upgrades that solved the lubrication issues that plagued the '86 and earlier units.
It actually has five sides. It measures 13 1/2-inches long and 13-inches wide. The Turbo 400 pan is longer than it is wide. The part of the pan at the rear of the transmission looks like the lower part of the state of Texas (really).
Re: 700R4 and TH400 Torque Converter? No it will not. The 700R4 has a lock up torque converter and the TH-400 does not. You will need to buy one based on the year of your trans too.
You can expect to use between 11 and 12 quarts of fluid in the stock version.
Depending on the tail shaft housing, its overall length can either be 27 5/8 or 30 5/8 inches. The 700R4's case length is 23 3/8 inches and its overall length is 30 3/8 inches. The TH350 weighs 120 lbs., while the 700R4 weighs 155 lbs.
To change from 4wd to 2wd and vice versa, just remove enough of the guts so you can get to the retaining snap ring on the front of the shaft. Remove ring, pull shaft, insert new shaft, replace ring, and reinstall parts you removed. However your 2wd case is weaker than you 4x4 case.
The TH400 is an automatic shift, three-speed, longitudinally positioned transmission. It is widely regarded to be a supremely durable and legendary transmission. The TH400 is conservatively rated at 450 ft. lbs.
For cars that weigh less than 3,200 pounds, launch violently, or are traction limited, the Powerglide is the best choice. In these types of applications, a Powerglide is the ultimate in consistency as well. On the other hand, for cars that will see any street time at all, a TH400 is a better option.
The TH400 is the largest of the common GM auto transmissions, but still surprisingly compact in light of the immense power they can handle. There are two significant variations of the TH400. The TH375 was a version of the transmission used from 1972-1976 in smaller displacement cars.
