Welcome Nick, usually everybody has a good time here <G>
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>The first thing to do is replace the transmission. It is not the
>correct model for the car, I believe its from a 71', and its running on
>borrowed time. I would like to replace it with a correct year model, non-OD.
> I would like to use this chance to get performance upgrades, mainly better
>highway cruising at top gear. Has anyone altered gearing ratios? Are there
>suppliers who make different gear ratios? I have also noticed some writers
>mention 5spd tranys, what is the story with those? I am not worried about
>keeping the car stock, so has anyone replaced the transmission with another
>makes?
> Rear differential rebuild or replacement. Any suggestions on limited
>slip settups or altered gear ratios here....
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There really aren't many (if any) ratios out there. It's hard (and
expensive) enough just to get the original ones. If your looking to
improve your highway cruising speed by reducing the RPM's, then replace
your existing three rail, early box with a later, single rail marina type
box WITH overdrive. It’s a little more work, and requires a few extra
parts, but well worth it. MUCH easier than adapting a 5 speed from
something else, and for these engines more than adequate.
The rear end ratios vary anywhere from 4.11 to 3.27 depending on what year
and vehicle you take it out of, or what you want to re-build into. Chances
are yours is 3.89:1
The ovd will drop the freeway RPM's by around 1000 and afford more relaxed
cruising, but still allow reasonably quick (for a Spitfire) acceleration.
limited slips, or torque sensing diff are available, but very expensive.
My Quaife carrier alone was $750, and you still have to install it or have
it done (more $$)!
Barry Schwartz in San Diego, CA
Bschwartz@encad.com
72-V6/5sp Spitfire ( daily driver )
70 GT6+ ( when I don't drive the Spitfire )
70 (sorta) Spitfire ( project )
73 Ford Courier ( parts hauler )
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