Thread: Th 350 swap

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I have a '49 chevy truck with a 75 nova subframe, sb350/th350 combo with a gm 10 bolt rear end. I want to go with an overdrive trans like a th700-r4. My questions are, besides moving the trans mount back, what other modifications will be required? Are they the same length or will I have to shorten the drive shaft? Will the shift linkage match up? Any other considerations?

i think you will have to shorten the drive shaft, also you will need a shifter with an overdrive position.

The 2004r is the same length as the th350 but you still have to move the cross member back 6".

you did noy say which 350 you have a short shaft is 3 3/16 shorter than a700 mid lenght is almost same The shift linkage is same spot cooling lines same you must lock-up the torque converter when the truck is in 4th gear or it will over heat If you use a 700 from a fuel injected car or truck You can wire the lock-up out side the trans if it has a normally open 4th gear switch. You need an ohm meter there is a wire harness on the trans the rear wire should ohm out as an open curcuit if not you need to change the 4th gear switch to a normally open one If it is an open switch you need to put a 12 volt sorse to the front outer wire and connect the front inner wire to the rear wire all done with just a butt connector . locks up 4th gear only .The crossmember will have to be moved back 2 in. unless your subframe has holes to align subframe to a 400 trans then you can use a 700 tailshaft housing that has a boss for a trans mount and it will bolt right up. You also must run a t v cable to control the shifts