Mercomatic

Thanks again for your post.
You are right that the Edsel amd Merc are both same size[410 and 430] trans. They are single range.
The difference between the single and the dual is the sprag clutch feature,I see. I did ask an old trans builder about retrofitting to make a single range a dual. He told me it couldn't be done. I thought as you,that a valve body change would make it work.
The Edsel case is same as Merc with the exception of a electric solenoid to safeguard against accidental trying to engage reverse while moving forward. Most of the solenoids have failed and have been disabled. Still can use a Merc trans regardless. Tom