Harley never used wrinkle,just a semi-gloss black. They are silver thru '69. Wrinkle does not disipate heat,that's an old bikers tale. Any coating slows the disipation of heat, the thicker the coating the slower the heat disipation. In the old days we used to see XLR's with no paint from time to time. They just sprayed the cylinders and heads down WD-40 after the race to keep them from rusting.