I'm curious, Tom, what track are you racing at that the 4:55 is too low?
I race MiDiv (Heartland Park, Hallett, Mid-America, Gateway, Memphis) and
run a 4:55. The only place it seems to hurt is the Memphis straightaway (the
full end-to-end dragstrip), but then I'm glad to have it for the run down
the backside through the M's, etc.
(I also autocross, so good for that too).
Back when Mid-America Raceway (St. Louis, not Omaha) was in use, my brother
raced my car and used the 4:55 there even though it, too, ran the straight
the full length of the dragstrip and runout, because he gained more between
1 and 10 than he lost between 10 and 1. When we ran at Hutchinson, an
airport circuit, that was the only track the 4:11 paid dividends.
Also, in what way does your intended replacement not match up? Do the bolt
holes not match, or does it not fit in the case, or what?
BTW -- '63 would be a Mk. I, not Mk. III. Mine's a '64 Mk. I. I'm not sure
of the specs, but seems I recall the diff case got bigger in later models,
or maybe that involved using a GT6 rear. Call Ted Schumacher at TS Imports
and pick his brain. 800-543-6648. He's answered similar questions for me in
the past.
--Rocky Entriken
----- Original Message -----
From: "Tom Britt" <zhbmacaw@worldnet.att.net>
To: <fot@autox.team.net>
Sent: Wednesday, September 03, 2003 12:21 PM
Subject: changing spitfire gear sets
> Friends:
>
> I am attempting to change my 73 spitfire, rear end gear ratio from the
> stock 3:89 to a 4:11. I have a 4:11 ring and pinion from a 63 mark III,
was
> told it would match up, but it doesn't. I am a low budget vintage racer
and
> looking for advice to solve this problem.
> Any help would be greatly appreciated.
> I also have a 4:55 ring and pinion, to low a gear for our track, probably
good
> for autocrossers, if anyone interested.
>
> Tom Britt
> Spitfire racer
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