Author Topic: 1969 M20 differences-ID 3950356 vs.3946797  (Read 1186 times)

ko-lek-tor

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1969 M20 differences-ID 3950356 vs.3946797
« on: April 29, 2013, 04:11:21 PM »
I have never been able to find a definitive answer as to the difference in M20 trans. options for RPO L48,L34,L35 & lM1(3950356) vs. Z28&L78(3946797). I reference the AIM M20 A1. Hoping someone will educate me as to How to ID one from other when tag on side cover is missing. Somewhere I thought I read it had to do with speedo gear, but that may explain the Z rear axle, and not L78.... see my post regarding "SS 396 rear axle ratios" below. I hate to post if this has been covered already, but I pour over these posts daily and do a lot of searching and cannot find the correct information. I promise, I will buy Jerry's book someday, but until then? I guess, I too would like to be regarded as an "expert" someday on at least 69 Big Block cars. Thanks again CRG, Bentley B.
James to strangers, Bentley to friends
1969 SS/RS 396 coupe Hugger Orange X22 712 bought in 79
1969 SS 350 coupe LeMans Blue 713 bought in 79
1969 307 4spd. coupe Daytona Yellow 711 bought in 85

bertfam

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Re: 1969 M20 differences-ID 3950356 vs.3946797
« Reply #1 on: April 29, 2013, 04:24:02 PM »
Yes, the main difference between all the Muncie M20 transmissions is the speedometer gearing, which depends on the rear axle ratio and the size of the tires. For instance, a 3.31 axle ratio with F70-14 tires wouldn't use the same speedo gear as, say a 3.73 axle with E70-15 tires. The MPH would be off.

Ed
 

ko-lek-tor

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Re: 1969 M20 differences-ID 3950356 vs.3946797
« Reply #2 on: April 29, 2013, 05:37:07 PM »
see post on axle ratios,thanks.
James to strangers, Bentley to friends
1969 SS/RS 396 coupe Hugger Orange X22 712 bought in 79
1969 SS 350 coupe LeMans Blue 713 bought in 79
1969 307 4spd. coupe Daytona Yellow 711 bought in 85