Off the top of my head, I part of 2 answers.
Lee and Richard Petty both won several champoinships in Grand National/Winston Cup. I don't know the exact years, 1960's for Lee and 70's & 80's for Richard
Dale Earnhardt Sr. & Jr. both won championships. Sr. in Winston Cup 7 times from late-80's through mid-90's. Jr. won the Busch Series title back to back in the late 90's.
I want to say the Allison's might be another pair.
Lee and Richard Petty both won several champoinships in Grand National/Winston Cup. I don't know the exact years, 1960's for Lee and 70's & 80's for Richard
Dale Earnhardt Sr. & Jr. both won championships. Sr. in Winston Cup 7 times from late-80's through mid-90's. Jr. won the Busch Series title back to back in the late 90's.
I want to say the Allison's might be another pair.