Author Topic: 1969 M20 differences-ID 3950356 vs.3946797  (Read 743 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.
Putting you First...Keeps me First. Talent on loan from God. Helping the hobbyist and exposing the fraud
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

Ed_B

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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.
Putting you First...Keeps me First. Talent on loan from God. Helping the hobbyist and exposing the fraud
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