<VV>Overdrive

[Padgett]

>Way back when I can remember cars that had electric overdrive switches. 
>When pressed, the unit activated the overdrive, which in essence, added a 
>gear to whatever gear you were in. I also seem to recall seeing the unit 
>itself bolted to the tailpiece of the regular transmission.

Laycock de Normanville. Introed in 1948 and used mainly on English cars. In 
the US the Borg-Warner overdrive was more common (pull a T-handle) postwar 
accessory.  Columbia had a whole series of two-speed rear ends prewar and 
Hallibrand made their fortune not in wheels but in the "Halibrand 
Quick-Change Rear End" . Most modern I recall was the Hone-O-Matic. All 
wonderful devices but designed for conventional inline powertrains.

In the 1970s there were a series of articles on how to adapt a BW O/D to 
the Saginaw gearbox (had to drill one hole). Problem is they all bolt to 
the output end of the gearbox which is currently bolted to the  gearbox. To 
add would require an even longer input shaft,  a special O/D output shaft. 
and some place to put the two foot longer powertrain.

It was mentioned that an O/D top gear might be fitted. The problem is that 
in a conventional transmission, fourth gear is not a gear at all but rather 
the input shaft is locked to the output. 1:1. Same for the PG trans. Geared 
top gears are common in transaxles but not the Corvair transmissions.

So for top gear in a Corvair, the only gears doing anything are in the 
differential and being sandwiched betwen the engine and transmission, there 
is no room for a Columbia or Halibrand system.

This makes the easiest (though requires considerable searching and work) 
answer is a 3.08 gearset (not common) and a four speed with a 3.65 first 
gear (FC), only available up to 1965. Easier is a 15" wheel on the back 
with a tall rear tire (I keep meaning to try a 225x70x15 to see if it 
clears, a 215x65x15 fits nicely).

Anything else is going to be ex$pen$ive.

Padgett

ps occasionally I deliberately misspell a simple word to either create a 
stop or to emphasize a concept. Speeling wrong "rong" does that. Artistic 
license.