Dalet

Hi,

I'm looking at changing out my st300 switch pitch Jetaway transmission on my 65 Cutlass vert for a th350 BOP to get a little better low end power and maybe a little better mileage. Are there any "gotchas" in doing this swap? Will my existing torque converter work with the th350 transmission or should it be replaced? Any lessons learned would be much appreciated. Thanks

oldcutlass

The torque converter needs to be replaced as its not compatible. You'll need to use a universal type kickdown cable and bracket. Everything else will work. I did a similar swap but used a t400, you'll have to get used to how the indicator works because since its a 2 speed it won't exactly line up with the 3 speed. I count clicks to ensure neutral and drive.

joe_padavano

This is an easy swap. As Eric points out, the biggest problem is that you need to rig a kickdown cable to the carb. The 2.52 first gear will make a big difference off the line vs. the 1.76 first in the Jetaway. Top gear is 1:1 for both transmissions, so there is no change to highway economy or RPMs.

Dalet

Thanks for the info. I picked up a used TH350 yesterday. He had planned to use it for his firebird but then changed his mind. When I got it home it looks like it is a lockup torque converter model but I am not absolutely sure. I has a 4 prong electrical connector on it and C10 on the bell housing. The only other markings I could find were MX2 on the housing and the partial vin of 48X126024 (the 8 may be a B, I can't be sure).
If this is a lockup version TH350 am I opening up a can of worms putting this in my car? Any info would be great. Any chance of a decode of the VIN number? I am not in this for much money but would like to know more before I go through doing a re-build in it.

Thanks