I measured the bellhousing runout and pilot bushing ID to input shaft pilot "tab" OD and all was within spec. So, nothing abnormal was found with the clutch, pressure plate, throwout bearing, pilot bushing, bellhousing, or clutch fork.
My existing Muncie M21 has had weld repair performed on the mounting ears of the case. So, instead of rebuilding this unit, I'm leaning towards starting completely fresh.
I spoke with the folks at Auto Gear (
https://www.autogear.net/motorsports/) and should be ordering a Muncie M20 from them in the next few days.
Here's the specs on their Muncie:
BRAND NEW Auto Gear "Syracuse" four-speed manual shift transmission/gearbox with Auto Gear/Antonio Masiero 'Muncie' M20 gearset (2.52 / 1.88 / 1.46 / 1.00 ratios), ONLY with 10-spline input, 27-spline output, and passenger side speedometer.
Choice of 7 or 8 tooth speedometer drive (typically 7-tooth for 3.55-4.10, 8-tooth for 3.08-3.42s).
It uses the following:
Auto Gear American-made "Supercase"
Auto Gear American-made C355 aluminum midplate
Auto Gear American-made heavy duty tailhousing
Auto Gear American-made, Oilite(tm) Bronze-bushed sidecover
Auto Gear American-made cast STEEL shift forks
Antonio Masiero (Italy) M20 gears (2.52 / 1.88 / 1.46 / 1.00) w/ 1-inch cluster gear
Antonio Masiero (Italy) Auto Gear-designed synchronizer hub & lightweight 27-spline mainshaft (tighter fitting hub-to-mainshaft fit [40-spline press fit and zero lash])
Antonio Masiero (Italy) forged synchronizer sliding clutches
Forged high-silicon bronze synchronizer "blocker" rings
Auto Gear-designed, Antonio Masiero (Italy) produced T10-syle reverse gears (no more chipped up reverse gears!)
Hopefully, this will do the trick...
Daniel