Upon starting my 68 Camaro successfully after the Cam swap and installation of the Holley Stealth Ram and all of the attendant plumbing, wiring, and sensors, as well as the installation of the TPI serpentine belt set-up, I was ready for a little tuning. With the engine running I kept a very close eye on the Holley wide band air fuel ratio gauge on my dash to make sure I wasn’t running too lean. The Holley Commander 950 base map I had chosen (WBmp3008) seemed to be close enough—a little lean but still safe at around 15:1. One thing I had to figure out was the idle speed. I had set it in the software at 800 once the car warmed up (it starts cold around 1100 RPM). This was down about 50 RPM from the WBmp3008 base map since I had considerably less overlap than the cam used for the basemap and figured it would be easier to get a nice idle. But the Camaro was actually idling about 1100. It turned out I needed to adjust the idle air screw on the side of the throttle body as well as set the actual timing on the car to match that which the Holley. A few turns of the set screw closed the throttle blades enough to get the idle down where I wanted it. I had to purchase a timing light with a dial back feature in order to match the timing on the distributor with the 23 degrees the Commander 950 was giving the Camaro at idle, but it was straightforward with the correct tool.
I also noticed a water leak from around the water pump, which meant the block had to be mostly drained of coolant and the TPI serpentine accessory drive had to come mostly off the Camaro so I could pull the long style reverse rotation water pump and try again with a different set of gaskets. The ones that came with the water pump were sort of a cork-like material and I used the Chevy specification for the bolt torque as well as a thin layer of RTV sealant so I was a little surprised by the leak but I used a FelPro composite-type gasket set re-prep’ed the block and didn’t have any more problems.
The Camaro was running lean in the lower RPMs due to the higher volumetric efficiency of the shorter-duration cam I was using relative to the one used for the base map so I added ten percent to the pulse widths in the first three columns of the fuel based map and tapered them off to the rest of the map where the map stopped being lean. This meant at the higher RPMs the Air/Fuel ratio was a bit rich which I wasn’t too worried about so I left that part of the program alone. When the dual Spal fans kicked on the idle would start to surge back and forth 50 to 100 RPMs around the set point so I played with that quite a bit. The Commander 950 Software has two features to keep the idle steady, one involving fuel trimming and one for adjusting timing to keep the idle steady. I enabled both and still found the idle to hunt a little. Good enough for a test drive though.