I have followed the discussions about overdrives and 5-speeds with
interest.
My TD has a TF (1:4.875) rear end which matches nicely with the rebuilt
and ported engine. I feel the car is at peace with itself until I get up
above 50 mph, where I find myself reaching for a 5th gear.
The standard solution is to "upgrade" to a 4.55 or 4.3 MGA rear end . .
. not an uncomplicated or inexpensive proposition and with some
compromise in low gear performance (the exent of the compromise varies
in description from mild to significant.)
Another solution is to change to a Datsun B-210 5-speed transmission,
which I assume has an overdrive 5th gear. Again not inexpensive (about
$1800) and with some philosophical drawbacks as to originality and
honoring the Mark and all that.
There is an outfit that makes overdrive units that are designed for
interposing into a split driveshaft in any vehicle . . . cost about
$1500 and concerns over whether there is room along the T car's drive
train to accomodate the unit.
There were some postings on the UK web site a few months back about an
Austin Healy overdrive unit modified to fit a TD, but it hadn't been
installed yet.
Somewhere out there there has to be an add-on overdrive unit that we
could adapt to the T cars . . . possibly mounted at the rear of the
drive shaft under the storage area.
Until I find such a thing, I am inclined to stay where I am, enjoying
the low gear performance. I take comfort in the DuBois' experience with
high rev motoring. I think that's how these cars were designed.
Andy Moyce
Oakland, CA
52 TD
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