I was surprised to see that most catalogs are listing pistons as "Pan/Shovel". Didn't they all used to list them as Knuckle/Pan/ Shovel? No matter, any piston listed for a 74" Pan or Shovel will work in a Knuck. Personally I have been using cheap imported pistons and having the skirts teflon coated for about the last 10 or 15 years. I have just started adding a ceramic coating to the domes. When you add the cost of the coatings you are still considerably under the price of a Wiseco or S&S, and in my opinion have a piston with a lot better chance of survival. Just my 2 cents worth.