What the heck. I'll be the odd duck. A low deck 470 with the 240 heads would be killer. That's the 3.900 stroke with around .625 lift roller cam. Am sure some on here will agree. It's just a great combination. My nephew built one for his 68 road runner. He went from a 451 to 470, says it scares him to drive it on the street. Maybe he will see this and put in his 2cents.