This unit is a drop out of a Corvette that we ended up parting out. What the numbers mean across the top of the transmission 266 - first gear ratio mn6 gearing, 17845 is RPM serial number, 0917 is the build date, and the A C lettering is factory stampings. Here is a list straight off of RPM's website on that was all done to the transmission.
	
Media Blast Transmission Case
	
Solid Synchronizer Keys
	
Bronze Fork Pads on All Gears 1-6 Including Reverse
	
Bronze Shifter Bushing When Applicable
	
Steel 3-4 Shifter Fork
	
RPM Modified 1-2 Shifter Fork
	
Hand Fit Sliders and Hubs
	
New Compressed Carbon Blocking Rings
	
Micropolish by Performance Metal
	
Cryogenic Processing by Performance Metal
	
Assembly to RPM Specifications