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Discussion Starter #1
Hi All, Long time reader first post (not including the one incorrectly posted under the 2004 GTO forum). Lots of great info on here but could not locate the answer to my latest project dilemma. Currently swapping a third generation (fine spline) muncie into a 1970 GTO, originally a second generation M-21 car. I need to relocate the speedo cable to the passenger side. The '72 manual I have shows this passenger side connection but no routing diagram. I would like to route the new cable as close to how the factory did in '71 or '72. Any explanations or photos would be much appreciated. Thanks in advance and for all the other info I have already found!
 

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First, the '71-72 Muncie 4speed speedo casing is longer. The original M22 is in my '71 T-37 Coupe. am booked up this week, could get it up off the floor, possibly early the following week & get a pic. There is some form of clip I just can't remember exactly where it attaches.
 

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Discussion Starter #3
Thanks for the info Pinion head, the casing I have is longer as you describe. The extra length is mostly behind the rear transmission mount. Those bolts now sit centered on the slots in the original 1970 cross member in case anyone is curious or considering a similar swap. I plan to keep the original driveshaft uncut and am working on sourcing a shorter replacement per your reply post on drive shaft lengths. My measurements confirm your 56.00" correct for the smaller tail Muncie. When you have time for photo of that cable/clip it would be most helpful, no rush as I know it is a pain to get underneath and without a driveshaft, I will not be speeding. Your T-37 with a stock M-22 sounds awesome!
 

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Discussion Starter #4
Quick update and thank you: I was able to connect the two-part speedometer cable to the passenger side connection of the gen 3 M-20 by replacing the lower cable with a slightly longer 20" one. Routing is likely not stock for a '71 model but we will see how it holds up.
Big thanks to Pinion Head for the posts on driveshaft lengths elsewhere on these forums (http://www.gtoforum.com/f12/measuring-drive-shaft-opinions-needed-105762/#post820994)
Sourced a used TH-400 driveshaft and seems to be the perfect fit for the large output gen 3 Muncie which is longer than gen 2.
 
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