70 Lt1 Trans

[Curt S.]

I need to know if the close ratio trans was mandatory for 70 Lt1 or if wide ratio could also be chosen. Thanks in advance Curt

[Terry M.]

Re: 70 Lt1 Trans

Either one.

[Wolf S.]

Re: 70 Lt1 Trans

mine has the close ratio m-21 trans

[Mike G.]

Re: 70 Lt1 Trans

mine has a close ratio m-21

[Keith L.]

Re: 70 Lt1 Trans

OK, I'll play
Mine has the close ratio M21

Maybe we should tell what rear as that may play a roll

3:70

[Terry L.]

Re: 70 Lt1 Trans

both of mine are M21
one has 4:11 the other is 3:55

[Michael F.]

Re: 70 Lt1 Trans

my 70 has m-21 with 3.70.....I believe m-20 came with 3.55 as standard.

[Dave S.]

Re: 70 Lt1 Trans

my 70 has m-21 with 3.70.....I believe m-20 came with 3.55 as standard.

Mine is M-21 with 3:70.

[Scott L.]

Re: 70 Lt1 Trans

As Terry mentioned, the LT1 could be ordered with either M20 wide ratio or M21 close ratio.
Standard axle ratio for the M20 wide ratio transmission was 3.55
Optional economy ratio 3.36, performance ratio 3.70.
Standard axle ratio for the M21 close ratio transmission was 3.70
Optional economy ratio 3.55, performance ratio 4.11

As keeper of the 70-72 LT1 survey, I can say that all have appeared. This holds true for 1971 and 1972 as well.

[Kenneth H.]

Re: 70 Lt1 Trans

Mine is M21 with 4.11 rear.

Scott, is info from the '70-'72 survey available to members, and if so where can I find it? Also, I know that my LT1 was not part of the original survey. Is the survey ongoing and is there a way to add the info from my LT1 to the survey?

Thanks,

Ken

[Scott L.]

Re: 70 Lt1 Trans

Ken,
The survey is still going on, actually, 25 years now.
The last time results were published was Spring 1992.
However, stay tuned, I recently sent the updated survey to Vinnie Peters at the Restorer. Hopefully he can find room, the summary results and survey forms take up a lot of real estate.
I have attached .jpeg's of the survey form. I needed to reduce size to fit, so clarity may suffer. If needed, send me email address and I will sent better forms.
Scott

[Stephen B.]

Re: 70 Lt1 Trans

M-21 close ratio

[Tim S.]

Re: 70 Lt1 Trans

M20 and 3.70. Runs like a scolded rabbit!

[Patrick B.]

Re: 70 Lt1 Trans

Scott:
I supplied the info for my 70 LT-1 sn 14297 many years ago to an LT-1 survey. I don't know if it was yours. If it is not already included I would like to add my info. I have had the car since 1972 when it had 8,000 miles and I have lots of documentation. For the last 28 years, I have run it with a ZL-1 427 out of a 69 Camaro which really kicked it up a notch. It scored the fastest time of day at the 1988 NCRS National Convention in Lancaster, PA with a 12.6 114 mph. The car still has less than 40,000 miles on it.

[Dan P.]

Re: 70 Lt1 Trans

M22, 456:1