So you''ve decided to slam four with a GM Muncie
It''s nickname is the "rock crusher" due to the noise generated by the gearset. The gear ratios are the same as in the M21, but the tooth angle is different. You''ll get more gear noise, but you''ll also get more strength. Advertisement. M20/M21 tooth angle vs. M22. Image credit where credit is due, I could not find an origin. Regarding strength, I have never seen official numbers but