Put playdough or clay or tin foil ball on top or radiator/bkt and gently close hood to see clearance.
BTW, pony did give dimensions of radiator. If you buy an aluminum radiator from the 100's of sellers, check the dimensions. Ask questions if dimensions don't jibe. Reas internet build blogs, Ask members here what worked. That is standard procedure for anything. Many sellers have no idea about what they are selling esxcept LS chrome dress up accessories and sun screens.
When you compare prices be sure to include shipping cost. They vary wildly. Some may be free.
Sometimes Rockauto can be a good drop ship choice. Radiator for 66 is $300
Others that are usually good. Summit, Speedway, Jeggs, Amazon
