Re: MUNCIE METAL TAG ID
 

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lynn</div><div class="ubbcode-body">From the assy manual for 1969 Camaro (don't know about Chevelle or 67-68 Camaro)

3950356 is for RPO M20 with L48, L34, L35, LM1
3946797 is for RPO M20 with Z28 &amp; L78
3950316 is for RPO M21 with L34
3946798 is for RPO M21 with Z28 and L78
3950318 is for RPO M22 with Z28 and L78

Evidently, from this and from the RPO spreadsheet file in pdf available at camros.org, you could not order a close ratio (M21 or M22) unless you had L34 (M21 only) or Z/28 or L78.

Now, for another question: Why is there a different tag number for the M20 behind a Z/28 or L78 as opposed to the one behind an L48 engine? They would be identical outside dimensions. The Z and the L48 would have identical shifters and brackets. Was there anything internally different between a Z/28 M20 and the regular small block SS M20? There had to be something different about these transmissions to warrant different tags. Maybe the standard rear gear ratio? </div></div>I don't think they had identical shifters.I don't think they had identical shifters. One would have had a Hurst and the other a Muncie.

Re: MUNCIE METAL TAG ID
 

All the four speeds in 69 got the hurst shifter.

I believe the answer to the question was submitted by crash: &quot;Different speedo gears on the main shaft...&quot; Crash

The Z and L78 would likely have the lower rear axle dictating different speedo gears to at least get close on the speedo.

Re: MUNCIE METAL TAG ID
 

12B641197 Thanks.

Re: MUNCIE METAL TAG ID
 

I noticed above that &quot;<span style="font-style: italic"><span style="font-weight: bold"><span style="font-size: 11pt">3950316</span></span> is for RPO M21 with L34</span>&quot; but I have the same tag on an M21 for a low mile L78 (4.10 rear) car. Would that be possible?

Re: MUNCIE METAL TAG ID
 

Calling all trans tag gurus.....(see above). Thanks!

Re: MUNCIE METAL TAG ID
 

An anomaly [img]<<GRAEMLIN_URL>>/dunno.gif[/img] why did they bother with a tag for L34 and L78 ? No differance in the M21, right ?

Mike

Re: MUNCIE METAL TAG ID
 

Mikey, I agree. I don't understand why there would be a different tag (and for that matter the trans construction) for a L34 vs L78 engine in front of an M21. Referenced car is original engine, tranny, and rear with owner history and multiple dealer and factory docs. What could matter (as far as differentiating M21 variants on the assembly line) is the speedo gear wrt the rear axle ratio.

Re: MUNCIE METAL TAG ID
 

There are 3 different speedometer drive gears used on the tail shaft in the muncies. The rear axle ratio will determine which one is used. That is probably why the numbers differ. If a speedo reducer adapter was used that may also reduce the number of different tags that were needed. Here is where I found the information, http://home.comcast.net/~chevelleengineer/speedo.htm it could come in handy. Clint

Re: MUNCIE METAL TAG ID
 

OK so what is 3968012WM ?

Re: MUNCIE METAL TAG ID
 

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Furback</div><div class="ubbcode-body">OK so what is 3968012WM ? </div></div>

I believe its for a 1970 M22 application.