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Shifting to Overdrive

Linn Richardson of Bothell, WA conceived the idea of building a Corvair 5-speed transmission in 1995. Linn formed American Boxer R&D, LLC, in 1998 to manufacture the transmissions. After producing 18 units, Linn closed the company and sold the assets to Ken Holm in December, 2005. Ken formed a new company with the same name in Maine. For more information, please contact Ken Holm.

The Corvair 5-speed is an adaptation of the ubiquitous Borg-Warner T5 unit. The modified transmission is designed for use a '65 - '69 Corvair (coupe, convertible, or sedan).

One advantage of the T5 is the large number of gearsets available. Possible 5th gear ratios include .53, .56, .59, .63, .65, .69, .72, .73, .76, .78, .81, .86, .90, and .99, depending on the first gear cluster that is used. First gear ratios include 2.95, 3.50, and 3.76 (compared to the 3.11 ratio of a '66 - '69 Corvair 4-speed).

The first prototype successfully finished road tests in the summer of 1998. Linn then enlisted the help of Steve Wren, a local Corvair enthusiast and experienced machinist, to translate the prototype parts into ones that could be manufactured in quantity and have great durability. Steve and Linn made a number of improvements to the prototype that increased the strength of several key parts.

A second prototype, incorporating Steve and Linn's improvements, was road tested and was available for test drives at the 1999 CORSA International Convention in Lake Tahoe, CA. Some pictures with commentary of that installation are below.

I own one of the first 18 units produced. I will eventually be installing it in my '66 500 coupe. When that happens, I will update this page with more information.

Update, January 2016: Several of the owners banded together to fix problems that emerged with the original design. You can watch some videos on YouTube to see the details and read this thread on Corvair Center to see installation pictures and more.

Second Prototype: Pictures with Commentary

For more information, please contact Ken Holm via email or web site.


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