Regardless of what buzzword is used (3/4-race, etc.) the bottom line is that a street-driven engine doesn't work well with a cam with more than about 270 degrees of lobe duration, intake or exhaust. Stovebolt engines don't play well with high lift because of the close clearance between the intake valve and the top of the piston. Flycutting the piston for valve relief reduces compression, and the combustion chamber shape limits the options for making a domed piston.
Because super long-duration cams MUST have increased compression to work right, the stovebolt's combination of oddball valve geometry and combustion chamber shape makes it difficult to benefit from a radical cam.
Jerry
