Quote:
Originally Posted by John V.
... My understanding is that in '71/'72, the M21 was not offered in any Firebird ...
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My understanding, and the Corvette always being the exception to the rule, is that divisions only got one close ratio per year/model line.
1970 Firebird = M20 or M21
1971 Firebird = M20 or M22
1972 Firebird = M20 or M22
1973 Firebird = M20 or M21
Quote:
Originally Posted by dadsformula
... The reasons were predictable, it was a way to continue the 455 without the HO features for marketing...
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That is a very interesting take on the matter - I never looked at it this way(!);
1972 Trans Am = 455(HO) + Close Ratio 4 spd (M22)
1973 Trans Am = 455(L75) + Close Ratio 4 spd (M21)
Effectively they both have the same displacement engines, backed by a close ratio four speed.
I wonder if the M22 was dropped for the same reason as the shaker being closed - the additional euphoric symphony, err, noise from the M22 may have contributed negatively towards the car's newly EPA(?) regulated noise levels as a whole...