Radiator swap

[Reece71]

My 71 has a HD 4 row radiator that is leaking all over. The radiator shop said it's trash and he could re-core it for about $500. He recommended getting a new aluminum one from O'rileys. He said they do a pretty good job and are priced right. I picked one up and went to install it last night and of course, it doesn't fit right; story of my life. The new radiator is a 2 row and the almost 3/4 inch thinner that the 4 row so pads and retainers are too wide. I know those trucks came with a standard duty radiator that was thinner, but don't know about any different retainers available. Any help to make this fit would be greatly appreciated. Thanks.