Vannin' Home Forums General Discussion Generic How To ..... Manual to Automatic Swap, '73 G20

Hi Everyone,

Long time reader, first time posting besides my intro. Thanks for participating in this forum, it has made for a great resource!

I recently purchased a '73 LWB G20, 350v8 with standard 3 on the tree. Id really love it to be an automatic, floor shift. Id like to consider an overdrive model but am very content with a TH350, as this was a factory installed item at that time. My main question is my parts list. Here's what I think I'll need in general, please feel free to help me add onto this list...

-Healthy Th350 Transmission
-Torque Converter
-Any factory wiring that is associated (or rewire, dont know much about this part)
-Any and all linkages

Can I use my driveshaft or should I try and do a flywheel to driveshaft complete swap? Crossmember can be re-used?

I have all the original service and overhaul manuals so I will probably use this to make sure I have everything transmission related, just curious about other parts that I can re-use. The original owner took good care of this van, whom I bought it from and pretty rare to hang onto these kinds of things I feel like these days. Its funny though, Im not sure why he has a GMC owners manual.


I see there are lots of favorites for floor shifting, which seems pretty ideal, I'd just like to have a longer stick I think.

Im sure there have been those who have done this,right? Any tips to share? Many many thanks!

Here's my '73. Besides being a little clunky to drive with manual and no power steering in LA, this thing is awesome. It's stout and is fun to run around town in.

If you want a auto w/over drive youll want a 4L60E.