it looks like we are going to have to wait to upgrade to a newer MH so I would like to upgrade the Turbo Hydramatic 400 to the 700R trans. Has anyone done this here? Seems at 65 mph its topped out, so...
I would look at the gear vender OD option. As others have said it will not be cheap and you will never get your money back from any increase in mileage. If there even is any.