This link will explain what Jifflox is:
Jifflox Manual on Hank's Truck Pictures
I didn't know what it was either until I started noticing some of these PIE K100s with mismatched tandems.
Anyway, I can't really use the decals you show because they're way too big for HO scale. They do look great, but they're about 3.5 times too large for my model. I suppose I could purchase them, scan the decals, reduce them and print on decal paper to HO scale, but I figure if I have to print them myself, I might as well just draw them out at the scale I need and arrange the numbers to match the PIE 26-xxxx series, along with the license plates, TT number, etc. But I sure do appreciate the response and the link. It wouldn't hurt for me to purchase the decals to use for reference.