Great work, Mike. Glad you're taking the obstacles with good humor. May as well. Besides, taking the time to make sure it's right means more trouble free play time later.
MAX cooling was part of the A/C package and trailer towing package. If you have the build sheet, check for 492 for the Max Cooling Pkg. My HiPo had air so I don't know if non-A/C cars had the package. There is nothing in the literature to indicate that that they did. FWIW the Formula S package which included the 273 HP did not include Max Cooling.