I cant say for the smallblock but use the Indy dual plane on my 63 thats a 440/493 and its a 99% street car that usually sees the track once or twice a year. But it gets a ton of street miles and I can say I really like how good the low end driveabilty is with the dual plane. And I must say I dont see many bigblock strokers around 490 to 500 cubes using a dual plane. But as for street driveabilty its great. I do want to try a single plane one day just to see if its faster at the track. Ron