Well perhaps I'm an anomaly, I've used nothing but BF 32's all my life, that's what came on my KR, new off of the lot. I used 32's on my 427 2 X 4 1966 Cobra, ran her up to 165 MPH, AND plenty of city driving, 32's in my 68 427 GT-E, runs like a scalded dog. As far as I'm concerned, the parts book says 32's for all HP for engines, and I couldn't agree more. I have several sets that I'll, probably never use, as they don't fail.