Now that I was on the street again, it was time to contemplate the next round of improvements. A couple of phone calls to Jeff Mortenson over at Classic Chevy Five Speed (now Classic Motorsports Group since they added other makes) put me on the correct path to lower RPMs. Using their RPM calculator, I determined the TKO 600 with the 0.64:1 overdrive was the best option for tire shredding torque off the line and good low RPM highway cruising—just over 2000 RPM at 65 MPH. In addition, with the lower first gear than the Muncie, the off the line acceleration with the 3.73:1 rear gear is equivalent to having a 4.23:1 rear gear with a Muncie! I opted for the McCleod shifter relocation and McCleod clutch and pressure plate, but ordered the deluxe package since I already had the scattershield there was no reason to purchase the Elite package. So off the Muncie came again, although this time I was doing the job solo. I was able to sell the M-21 with the bracket and shifter for $600 to offset some of my cost of the upgrade. I kept the shifter handle because it was an old chrome Hurst handle and I liked it.
While everything was apart I had the Lakewood Scattershield powder coated to match the subframe and the rear differential (Bengal Red is the color). Switching to the TKO 600 requires a new driveshaft, and unfortunately the one Classic Chevy Five Speed sourced from Inland Empire Driveline didn’t fit—the end didn’t fit into the tailstock of the rear differential. A for calls with Jeff Mortenson and tech support from Inland Empire revealed I had a beefier than stock tailstock (a 1330 rather than the usual 1310). Jeff was kind enough to replace the shaft at his cost but since he was such a swell guy I declined the offer and upgraded to the aluminum shaft. Other than the driveshaft snafu, the instructions from Classic Chevy Five Speed were dead on, so the install was straight-forward. They even have a video now. One of the things you definitely need to check is your runout of the crank relative to your bellhousing, I have a picture here showing how I measured mine, it came in at 0.004” total runout so I was in good shape. The TKO 600 weighs 99 pounds with no fluid in it, so I can assure you putting it in my Camaro while lying on my back in the carport was not the easiest task of my build-up, but it was one of the most satisfying.
