PG to TH350 or TH400

    Which Is Best?

    BB: I am 15 and my dad and I are in the process of restoring my '68 Chevelle coupe. It has the original 307 and Powerglide. I want to swap the two-speed Powerglide for a Turbo Hydra-matic 350 or 400. What are the real differences in the two transmissions? Am I better off keeping the Powerglide? What is involved in the swap? Is it different for the 350 than the 400? Planned for the future is a well-built 350 /350hp engine.

    S_: I did the swap in my '68 about 3 years ago. The TH350 is the right choice. It bolts right in, all you need is a new transmission mount, and you might have to move the crossmember to a different set of holes.

    BS: I put a TH350 in my '65 behind a 350 engine. The TH350 basically bolts in but I believe you have to find what is called a short TH350. Go with the TH350 over the TH400 unless you are running some real horse-power. The TH400 is stronger but it also uses up to 50 horses more than the TH350. The Muscle Factory (Anaheim, CA 1-800-762-0317) sells a conversion kit for the swap, although I kept all the original stuff (like drive indicator).

    MA: I just completed restoration on my 1969 El Camino that had a Powerglide. I rebuilt the Powerglide and packaged it for storage. Then I put a rebuilt TH350 in its place. I am so glad I did. It has a column shift. The only thing is that the indicator for R N D etc. doesn't quite line up. I have heard, however, that you can purchase a new insert to match the alignment. I chose not to in order to retain the original appearance. I kept the Powerglide so I can go to bone-stock if needed. TH350 is the way to go.

    SY: That is cool that you are fifteen and got a '68. That is how old I was when I got my first '68. TH350 is the way to go .You won't have to change the drive shaft that way. You didn't mention if you had a center console or column shift. If you have a center console a simple adjustment to the bolt at the bottom of the shifter and you should have a three speed. The indicator can be bought from Year One for about $13.

    Archivist: Tom Wilson

    [ Top Of Page | Archive | Team Chevelle ]