4 Speed O/D???????

Quite a few people use them. I am planning on using one in my 64 valiant. The later ones have a aluminum case, so one thing to think of is if you are planning on using it behind a high HP engine, there is a chance that one of the 'holes' will become oblong. (someone else can give the proper names and details about it)

It also has a large spread between 1st and 2nd gear, so it's not ideal for racing.

if you go to slantsix.org, and/or bigblockdart.com, they both have articles with lots of information on these.

Hope this helps.