1966 Riviera Overdrive Transmition

[Guest madisonight]

Getting ready to pull my motor this winter to detail everything and had heard a little about people switching transmissions to overdrive. Any pro's are con's to this, and what is the transmission of choice? Anybody attempt this. I like the idea of better fuel mileage and running the engine at a lower RPM's while on the highway. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

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[Guest Roostriz]

Pro's are better fuel economy, less wear on engine and accessories.

Con's are an expensive adapter to mate to the nailhead, 700-800 in the end I believe. And some minor fabrication for mounting.

Tranny of choice seems to be the 200-4r due to the dimensions and gear splits. There are various varieties of this transmission, the prefered ones are out of the semi performance cars (ie Grand National, Monte Carlo SS, Grand Prix). A few have done the conversion and there is a recent write-up in the Riview a couple months ago.

[RivNut]

Thanks for the plug. I wrote the article and Dave furnished the pictures of an installation in his '65. The write up is in the Jul/Aug issue of the Riview. I included sources and parts numbers for the swap. The adapter I used was from Eelco and it's priced at $449. The other thing that's probably going to be necessary is to replace the gears in the rear end. If you're currently running a 3.23 for example, your highway gear would be a 2.16. That would have your engine way out of its torque band on the highway. You'd want to go to something like a 3.73 or a 3.90. Your highway gears for each respectively would be 2.49 and 2.61. That will give you close to a 2,000 rpm engine speed at around 70 mph.

Ed

[Guest madisonight]

Thanks for the info guys, I knew I read it somewhere but could not remember, Will look it up and do some price shopping.