Dean,
Unless the UK Spits have different gear ratios in the gearboxes than US SPits
(and I don't think they do), the internal ratios are the
same throughout the series. The differences in the gearing is accommodated by
changing differential ratios. The diff ratios were not
changed when optional overdrive was selected, so in the 4 regular gears, there
is no difference in the engine rpm and the power output
to the rear wheels. But when the OD is engaged, you get the benefit of reduced
revs.
What's wrong with a 4 synchro box and D type OD? I have one in my Mk1 and it
operates flawlessly. I love being able to downshift to
first without having to come to a complete stop or worry about crashing the
gears.
Joe
Dean Rayner wrote:
> My Triumph advisors do not recommend putting a late gearbox-o/d into an
> early spit. The later gearbox has higher ratios for the greater torque
> produced by that engine. Also the diff ratios will be wrong.
>
> If you have a 3 synchro box, you should replace it with a 3 synchro with 'D'
> type o/d and not a 4 synchro box.
>
> Dean Rayner. (UK)
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