I did not remove my bumper when cutting the passenger side to widen the rad opening, only the grille.
I used a small circular cutting saw with a bi-metal blade. Hand filed the sharp edges after cutting. Drilled holes and used nuts and bolts to mount the passenger side. I ordered this Griffin Exact fit rad. It's 25.5" wide. I like that the stamped top looks OEM. I sprayed mine black top/bottom and front/rear faces using 2 different black products.
Griffin Thermal Products 5-70004 Griffin Exact Fit Radiators | Summit Racing
I bought the plastic shroud to fit from Summit and had no issues mounting it.
Mopar Performance P2785434 Mopar Performance Restoration Radiator Cooling Fan Shrouds | Summit Racing
Thanks 68 Sport Satellite! This is great info from you guys! I think I will try this myself and I'm going to use the griffin radiator and probably the shroud you posted. I have to bring my 69 RR to the body shop this week to get my new hood painted, when it comes back I'll probably start on this project,