I have an opportunity to pick up a Doug Nash overdrive unit for a good price. I can get a full rebuild kit for it as well. Since its used, I am considering it a rebuild able piece and expect to rebuild it before I install it. I have been considering a custom build OD transmission but, the availability of this unit is making me consider going this way.
I have a 1977 Airstream Argosy 28. Fully restored with a 454 thats bored stroked, balanced and blueprinted to a 496. I also have a TH 400 actually a TH 475 transmission that is also rebuilt and works perfectly. I have 4:56 rear end gears with 19.5 tires. Cruise RPM at 60 mph is about 3000-3200. I intend to get the noise of that much rpm down as well as save 30 % wear and tear on the motor and possibly even pick up a mile per gallon or so.
Anyone with any feed back experience, thoughts, advice ?