In the 1970 Daytona 200 Suzuki 500cc and Yamaha 350cc 2 strokes ran right along side the 4 stroke Honda, Kawasaki, Harley Davidson, Triumph, BSA, and Nortons. Ron Grant's 500cc Suzuki and Kel Carruthers 350cc Yamaha ran with the leaders until they broke down.
BTW great video, but the quality is terrible. Bruce Brown should have been at Daytona in 1970 filming On Any Sunday. I would really like to see some of that footage. I'm sure it is fantastic to look at and much clearer than Honda's promotional video seen here.
Scott