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Old 11-24-2021, 11:37 PM
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R 70 Judge R 70 Judge is offline
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Quote:
Originally Posted by racerboy View Post
Interesting. I was just looking at the PHS on my ‘70 TA and it is exactly the same as yours, except I have an option for floor mats ($6.15). I always assumed that my car was an M20/3.55 car, but this thread has me wondering. The car is restored but has all its original parts. Is it possible it has an M21 in it? How can I tell?


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Well without climbing underneath it you should be able to tell just by driving it.

With a M20 the first gear will be “shorter” and accelerate better initially in first gear (maybe go 45 mph in first at redline). It will also have a noticeable drop or “bog” when shifting from 3rd to 4th under acceleration.

A M21 will have “longer” first gear acceleration (maybe 50-55mph at redline) and will continue to accelerate better with less rpm drop between gears. You won’t have that “bog” when going from 3rd to 4th under acceleration.

I think that’s the best I can describe it

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1970 Trans Am

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