Our 32-579 Custom Cushions are a molded rubber cushion that will be used in place of the stock version cushions. All of our C3 Corvette Radiators and most of your standard GM early radiators that sit down in the cradles on the top and bottom have the standard u-shape type rubber cushion that goes in the metal brackets on the top and bottom. These fit over the header joint displayed here. Most early GM radiators that were all copper brass radiators had a nice defined lip from the copper brass style tanks that fit in that groove very nicely. When we developed the DeWitts™ Direct Fit® line, we ended up having to TIG-weld that across the top so it kind of blends in there and it's a little bit thicker than normal. We developed our 32-579 Custom Cushion to help secure it in place. It has the same shape cut out as the top of our radiator and fits in the same spot but it's locked from going side to side in any direction. Whereas, the stock cushion still fits, it would still work for you but there is a little more room to play and wiggle from side to side because it's not locked in there, we now must TIG-weld across it. When we molded the cushions, they're molded to fit our standard two row, one-inch Direct Fit® Radiator. We also sell our HP Series Radiator which is two rows of inch and a quarter. With that, the actual cut out and the channel doesn't match the top. So, if you do want to get a set of new cushions, you can still buy the 32-579 Cushions and trim them to fit. This locks it in tight to the top of the radiator and is a little nicer to use than the stock original cushions because you get a little more material that you're able to cut away from. Our recommendation is, if you're buying the Direct Fit® radiator, it's not a bad idea to get yourself a set of the 32-579 Cushions to help make it a more secure fit.