Average street to me is over 400 cubes, 10.4:1 comp, 300 plus cfm head, 557 cam , single plane 750DP and at least a 4.10 gear and 4800 stall convertor. lol
That probably is it if you average what people are racing, I just mean if you were to build a street strip version of a /6 273 318 289 302 340 350 360 383 408 440 454 460 etc..