> Does anyone have an idea of the history and population size of
> the TR4A with
> center pull throttle rods and springs, used with SU/HS6?
The information I have is that the conversion to HS6 happened at CTC62191,
and the last TR4A was CTC78684. So assuming continuous numbers, just
slightly over 16,000 cars originally had HS6.
How many of those are still on the road, I wouldn't know. But it's a
somewhat popular conversion for the earlier cars, so I would guess that
there are a lot more HS6 setups running around than there are late TR4A.
There's a pair hanging on my garage wall, currently planned for my "new"
TR3.
> The TR4A came in with the Z-S because of supply issues, I believe.
The ZS actually started mid-TR4, CT21471E according to the Moss catalog,
making roughly 18,000 TR4 and 12,000 TR4A equipped with them.
I vaguely recall reading somewhere that the SU-ZS switch was for cost
reasons, and the subsequent ZS-SU was for supply reasons, but I could
certainly be wrong about that.
> Then came back in at the end of the production run with HS6 and center
> pulls???
Better yet, the TR250, TR6 (non-PI), TR7 (non-PI) and Stag all had ZS carbs
too. They evolved over the years of course, mostly for emissions, but it's
the same basic design.
Note that HS6 throttle shafts turn backwards to H6 ...
Randall
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