swapping a th200 metric for a th350

It depends on if the TH350 is the same length as the 200- if the trannies are the same length you may get lucky and have the rear trans mount bolt up, otherwise make sure you use a TH350 torque converter with the new trans as they are not interchangeable, and you may need the shift linkage bracket off the 200 if you don't have one made for your car on the new transmission. It should be a pretty easy swap- I have not personally seen a 200 so I don't know all the differences... The TH350 is one of the simplest and most durable transmissions. Hookups include: 6 bolts on the bellhousing, 3 torque converter bolts, 1 or 2 bolts on the tail trans mount, two trans cooler lines, detent cable, and shifter linkage, and torque converter dust shield.

If you swap a 350/th350 combo in, you may need to move the motor mounts, otherwise expect wiring changes, exhaust changes, you may need a bigger radiator and shroud which will need new belts and hoses as well (unless you have a complete donor car)

Let us know what you choose! I am a big fan of motor swaps as long as the original motor wasn't special like a GN

If the same length water pump is used, no issues on accessories for an Olds 350. The linkage is adjustable and mount is the same spot. It has been years since I did one but think the drive shaft is the same.

If I recall correctly. The TH200 did not use a vacuum modulator, much like the 200-4R. Where as the TH350 does have a modulator and requires a vacuum line/ takeoff from the back of the manifold or carb.

The TH200 uses the throttle cable instead of the vacuum modulator. On my 260, there is already a port 'assigned' on the engine to use for the vacuum modulator for the TH350.

I opted to rebuild my TH200 since the gearing with the TH200 is better matched with my 260 and the 2.21 rear. However if I was to update to the TH350 I would have needed new throttle linkage and maybe oil cooler lines to the radiator. Other than that on a 78 it was a simple swap.

I did a 350/th350 swap this spring. The motor is a in & out swap, you don't need any new harness. If you get rid of the computer there will a lot of extra wires. The trans will bolt right in, the cooler lines are the same. The kick down cable will work in place of the 200 shift cable, a steel vac. line will need to be added, but if you are gettn a complete engine it should already have 1. The drive shaft is the same also. The shift linkage I had to rework but I have a floor shifter & headers, it was no big deal. The only other thing I did was to change the rear end gears to 342. It is a little to low, turning a lot of rpms on the hwy. I would have liked to see what the 307 would have been like with the gear change.

If the original carb is missing, get a 77-79 Qjet off an Olds 350 or 403.