3 to 4 Speed swap

[Red79Rat]

Hey everbody, I'm looking to swap out my transmission. My car has a Turbo 350 in it currently and I want to swap it out for a 200-4R. I've heard that it's almost a direct drop in without needing to modify the crossmember and I can even use my existing drive shaft. I have also read that they are also easier to turn (less driveline loss) then a 700-R4 and use the same torque converters. Any help, advice, and information is greatly appriciated. Thanks

 

[GNeric]

Crossmember... not sure, I know they have a different bend in them from 3spd location to 4spd location. Driveshaft is the same. Torque converters are different from Th350-2004R.

 

[borderline]

You will have to add in the TV cable bracket and the tranny lines are different, if I remember correctly. The tranny mount on the crossmember will be about 5 3/4" further back, and depending on the tailshaft length of the 350, the drive shaft make have to be shortened. This is based on swapping in a 200-4r, a 3 speed th200 has the same mounting spot as the th350

 

[GNeric]

A 79 should be the short tail 350 (6") so that should not have to be shortened. Larger cars, wagons, vans and trucks got the longer tail housings up to a point of turning to the 2piece driveshaft. Slight bending of the lines should still work (done lots of retrofits into smaller cars) and they line up. I did forget about the TV cable bracket like borderline said. (Good catch )

 

[SSedan64]

The 78-83 G-body don't have the Frame extension to use a stock 2004R Crossmember like the 84 & up does. It can be made or bought & added tho'.
G-Body Trans Swap Info>> Transmission Swap Tech
Summit, Jegs, Iceman have the Frame extensions & X-members.
Nice Tubular X-member >> Iceman Products