I thought all M21/22 where close ratio and had a 2.20 first gear. There’s a reason why I believe all Z28’s from 1967 to 1969 could NOT be ordered with any automatic and nothing under a 3.73.
1970-1972 Z’s had a standard 3.73 gear, option was 4.10, nothing under 3.73’s, GM new why...dog city.
I had the close ratio M22, then road race Doug Nash/Richmond 5 spd, face plated, now TR6060 T56 6spd combined with 3.73/27”
Tire, love it, second gear is 2.10....would never go back ever!!!
I drove an original 72 Z with M21/3.73, boy, so apparent it needed more O/A first gear ratio.
Here's a little story I will tell you about manual transmissions I learned back in the 80's. When we all use to race around town most guys back then had 4 speeds and lots were Muncie's. Now you had 3 choices for low gear ratios, 2.56, 2.52 and 2.20 which is the close ratio. After having a couple of close ratio Muncie's I always though they sucked performance wise, why? because they were sheet out of the hole for most bigger engines. I switched to the 2.56 low gear trans and while it was better I though when I started to figure out that the low gear was the key to performance. In 1983 I made the switch to start using Saginaw 4 speeds because even though they are weaker I still won a ton of races with them as the had a 3.11 low gear and a 2.20 2nd gear. I quickly learned that the Mustang 5.0 guys could win a lot of races as the 5 speeds they used in the fox body cars has a 3.27 low gear, so you could race getting quickly out of the hole and still use a decent gear for cruising on the highway, It was called launch ratio. I did break a lot of Saginaw's along the way, but being I could get them used out of all the Vega's, Monza's and other GM cars at $20 bucks a pop from the scrap yards, it didn't matter. One month I went through 5 of them and just bought some more. The key to making them last was not to power shift them which I did learn after some breakage. Sure you can race a 2.20 low gear 4 speed but the question is why? when there are so many good low gear 5 and 6 speed trans options out there these days with O/D. When you can get someone out of the hole by 2-3 cars it's pretty hard for them to catch you.