Muncie M20 vs. M21 vs. M22

cammer427 · #1 05-09-2010, 08:32 PM

There are a few companies producing new Muncies with different gear options than were available back in the day from the factories. My question concerns the Muncie transmissions that were equipped in cars back in the '60s/'70s (factory gearing, etc.).

What were the benefits and disadvantages of the factory-spec M20, M21 and M22 transmissions? Which were better for what circumstances, types of driving (racing, weekend-only cruising, daily driving, etc.)?

Obviously the M22 was the most durable of the three. I've heard the M20 was best for off-the-line acceleration due to it's wide first gear (are wide-ratio transmissions truly better for off the line acceleration?).

**Fast67VelleN2O** · #2 05-09-2010, 09:27 PM

I have a Muncie in every single GM vehicle that I own. I like the M20 ratios better and most of my cars have 3.73's in them. M21 and M22 ratios are just a little to low (numerically) for anything that I drive on the street. You can buy an aftermarket M20 gearset now with the M22 gear angle if you are looking for the strength of an M22 gearset.

**SuperNovaSS** · #3 05-09-2010, 11:59 PM

M20s are the most fun to drive in my opinion. Everyone seems to want a M21/M22 without realizing what the actual difference is. The M21/22s just don't have the hole gear to make it with any gear numerically lower than 3.73.

Jason