Hi All,

I am seriously considering buying a 68 Cutlass S convertible with buckets seats and center console. It is a 350 2bbl with 2 speed trans. Can you tell me what would be involved in swapping trans (jetaway to 350)? Are the mounts the same, kickdown cables, etc? Would the console shifter still work?


Thanks, Joe

 

It should be a very easy swap. Every thing should bolt right in.
The shifter will work, P,R,N,D, will be good, you will not be able the manually shift to low range with your '68 shifter.
You may want to get the carb bracket for the kick down cable. You may want to get it from the donor car the trans came from.

Gene

 

Thanks Gene, I knew the bolt pattern would match up, but was not sure about the crossmember mounts and driveshaft length. The car has a 2bbl on it right now but I will probably change to a 4 bbl and look for a bracket for that. I don't have a donor car so will have to pick up a used 350trans or rebuilt.

Any guess on what rear would normally be in the cutlass with current set up? I need to get a good look at the axle to know for sure....

 

The trans cross member should have a few bolt holes in the frame to chose from. If anything it should bolt back in the same spot. The drive shaft is a direct fit. Use the shift lever bracket off the 2 speed.
It's hard to say the rear axle ratio. My '68 has a 2.78 ratio. You could have a 2.56 or maybe 3.08's I have a T-350 ready to go in, just need the kick down bracket.
Good luck
Gene

 

I have personally done this swap in a 1968 Cutlass. If you get the correct short tailshaft TH350, it is a direct bolt-in. Crossmember is in the same place, driveshaft is the same. The only difference is that the Jetaway uses an electric kickdown like a TH400. To use the correct A-body TH350 kickdown cable, you need to cut the appropriately sized square hole in the firewall to pass the cable through to the accelerator pedal. You also need to swap the pedal, since the TH350 pedals used on the 1969-1972 cars have an extra tab for the kickdown cable to attach to. Alternately, you can use the kickdown cable and carb bracket from a 1970s Olds and connect the cable directly to the carb lever.

Your speedo cable will connect to the TH350, but of course the speedo drive gears in the new trans may not be correct for your application and may need to be changed. Cooler lines will bolt right up.

You will need the correct bracket that holds the shift cable to the trans pan. These are available repro. Shiftworks sells new three speed shifter quadrants for the stock floor shifter. They also sell the indicator plate for the console.

 

Thanks Joe!

I am familar with the kickdown cable through the firewall. I had a 77 cutlass that I bought with a odd fire buick v6. I swapped an Olds 350 eng and 350 trans from a 74 Cutlass Salon. I had to drill and file myself a square hole in the firewall for that as well. Thanks a million for the info on the bracket for the shift cable.
Joe

 

Do they have same transmission lines?

 

The lines should work fine.

I swapped a TH350 into my brother 63 impala, 283 4bbl with a Powerglide trans. The first gear ratio of the Powerglide (and your Jetaway trans) is about the same as the 2nd gear ratio of a 350 trans. The addition of a low first gear really wakes up the performance. My brother thought I did some serious engine work to the car, he said it felt like it had a extra 50 hp.

 

I’m doing the swap soon thanks for all the info

 

Does anyone have a pic of the square cut out for kick down cable?