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Re: Overdrive add-ons

To: Barry Schwartz <Bschwartz@encad.com>
Subject: Re: Overdrive add-ons
From: Andrew Mace <amace@unix2.nysed.gov>
Date: Wed, 21 May 1997 12:06:15 +0600 (EDT)
Cc: triumphs@Autox.Team.Net
> Ben writes:
> >I have a late 1200 Herald Saloon with a 1500 Dolomite engine.
> >As the gearbox (as far as I'm aware) is the original 1200 one...

Barry answered:

> Ben,
> The overdrive will allow more relaxed cruising by lowering the rpm at
> freeway speeds.  It will not give you any performance gains, but will
> probably improve your mileage on the freeway - and will NOT improve the
> reliability or power handling of your transmission as you use your existing
> tranny and simply bolt an overdrive on to the end where the tailshaft
> was...

> If it's square as opposed to round than you
> have an early no-synchro first (crashbox, Andy M. are you listening?)
> transmission....

Yeah, Barry. Sorry, I did doze off for a second! :-)

First, check the serial number for the gearbox: GA prefix would be a
Herald box. Second, and to supplement Barry's excellent advice, what
differential are you using? With the Dolomite 1500 engine, it seems likely
you could upgrade from the Herald's original 4..11:1 diff to a later (and
beefier to some degree) Spitfire's 3.89:1 or perhaps even the 1500's
3.63:1. This is pretty much a bolt-in thing, but involves new drive axle
and driveshaft U-joint flanges (to match the larger shafts on the newer
diff.) and likely an upgrade to the swing-spring setup as well -- all
worthwhile improvements with the bigger engine. 

--Andy

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* Andrew Mace, President and                *
*   10/Herald/Vitesse (Sports 6) Consultant *
* Vintage Triumph Register                  *
* amace@unix2.nysed.gov                     *
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