I’ve been looking for the right trans for my ‘60 El Camino and I stumbled on a Muncie horde last week and picked up a M20. Casting numbers and date codes suggest it came out of a 69 Tempest/Lemans/GTO. He had around 7 transmissions in various states of disassembly. Mine had no side cover but there were a dozen in a box so I picked a clean one with a good spring in it. I noticed later from the casting number it seems to be earlier, like 64/65. There was another pile of shift selector shafts, so I picked a couple late style ones (bolt instead of stud) to match the reverse one installed on the trans. When I test fit everything this weekend with shift arms on, I found that the shift selector shafts can slide in and out like 1/8” to 1/4”. I’ve never had a Muncie before, but that seems weird. Do I need a late style side cover to go with my late style shafts? Is the in out motion normal? I also got a hodge podge of Hurst shifter parts. I think I have everything I need other than some bolts and a late style reverse arm. The shifter body, Mount, and arms are definitely Hurst. The shift rods seem extra fat and the adjusters are different than the other Hurst stuff I have though. Are they off brand? Old Hurst? Just weird?
Compare the linkage in the lower photo to yours , it’s the Hurst installed at the factory in my ‘73 350 Cutlass. OEM Hurst had no synchro stop bolts and the clunky linkage.
You have factory Hurst shift rods with an adjuster positioned by two nuts. Hurts units used a screw on adjuster and didn't need nuts, also because there is no intermediate adjuster, your throw will be different. I've used real Hurts screw on adjusters with factory rods and had no problem. You can find them on the Web for about $8-9 each.
Ok, so I have factory OEM Hurst linkage. Thanks guys! I hadn’t thought about the difference in throw. I better bolt everything down and see if it’ll shift… Here’s a comparison between new Hurst linkage for a T10 and what I’ve got for my Muncie. Maybe I could bore and rethread the aftermarket style adjuster? The shifter body looks like a normal aftermarket Competition Plus. The internet seems to think body 2083 is pretty normal stuff. Anyone have any ideas about side cover difference? Thanks guys!
I have noticed side play on my bolt style shift selector shafts at least 1/8 and perhaps more, but only before the shift levers are attached. I wouldn't try this. I don't feel the adjuster is large enough for larger threads and a thin wall condition would cause failure.
Yeah, adjuster button walls would start getting thin if I bored them. 1/4” was an exaggeration, but there’s a fair amount of play with the arms bolted on.
The side covers were updated with a pin that had a head outside to prevent the early straight pin from becoming loose and leaking. This is the pin the scissors with spring are fastened to on the inside of the cover. I believe all the 7 bolt Muncie covers interchange. Your cover is the early version with straight pin. With shift arms fastened to shafts there should be very little movement in and out unless they have been ground thin.
I'm running an Auto Gear side plate in my '64 vintage M20. I had broken a stud on my OG one and opted for the new bolt type plate. It bolted right on and works well.
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