260 to 350 conversion

btlking
10+ year member

Registered User
hay guys does anyone know if a stock turbo 350 ****** will hold up to a 350 gm motor?

im going to pull my 260 tomorow and put in a 350 just wondering how long the ****** will hold up because i wont have a new ***** for about a month

 
not sure how much my car wieghs but its a 79 olds cutlass salon i plan on doing some motor work to the 350 in the future aiming for like 500hp after a little while

 
For a bone-stock 350cid the 350 Turbo Hydramatic 3-speed auto is more than adequate. I've seen more than a few of them mated to engines making up to around 330-350hp @ the crank and held up just fine.

If you're going to be doing work to it to make it around 500hp (and that will take some real doing - don't think a few bolt-ons will get you there) you'll want to look into getting that current ****** built to hold it or possibly think about sourcing a Turbo 400.

 
Automatic Transmission Description & Usage

THM200 - Light duty, "metric" 3 speed transmission.

THM250 - Used in small 4 cylinder cars (Vega, Sunbird, Monza) from 1973 to 1981 and some Nova/Camaro/Chevelle 6 cylinders in 1974 & 75. The 4 cylinder models have 4 large cooling holes near the torque converter, while on the "bigger cars" there are no cooling holes.

THM200-R4 - Used in GM rear wheel drive cars with the 3.8 V6, 305 & 350 Olds and 301 pontiac from 1981 to 1989. This is a 4 speed, overdrive unit.

THM350 - Medium duty 3 speed ***** used from 1969 to 1989, Used in Buick, Olds, Pontiac and Chevrolet cars and Chevy & GMC light trucks until 1987. Generally used in straight and V6 and small block engines. Generally able to handle up to 400 foot pounds of torque.

THM375B - This ***** is identical to the THM350, but is considered a heavier duty transmission.

THM375 - This transmission is a derivative of the THM400 sharing the external appearance of the 400. It'll be marked 375-THM on the bottom of the tailshaft housing. It's a light duty version of the THM400, has ABSOLUTELY NO RELATION to the THM375B, and was found in 1972 to 1976 full-size cars. The Turbo 375 was modified to accept the Turbo 350 driveshaft yoke.

THM400 - The THM400 was GM's Heavy-duty 3 speed transmission used from 1964 to 1990. Used on large displacement, high torque engines and engines with towing packages. Generally found in Chevy & GM trucks, cadilacs and large displacement engined, full size GM rear wheel drive cars.

THM700-R4 - 4 Speed transmission used in GM cars and light trucks with the 2.8, 3.1, 4.3, V6, Chevrolet built 305, 350 and 454 engines from 1982 to 1992.

 
yeah they turbo 350 will only be on it for about a month after i do the motor and make my power ill be putting in a racing ******

 
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btlking

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