what do the street heads do on the bench
I do those Street heads with either 2.200 or 2.220 valves usually. We can actually go even smaller and shrink the hole port per throat diameter, but I think the 2.200 valve is good all the way down to 400 cubes and 390-ish bores. On flow, up to .400, they are only a few cfm off the "Race" port, mainly due to more velocity from the small port. As the lift goes up, the bigger valve and bigger cross section start to show up. I have posted numbers from my bench before, but by comparison, they would be down about 10 cfm at .450, gradually working there way to around 15 cfm down at .600 lift. The big difference is what happens after .600 lift. The big port keeps going after .600 if prepped for high lift. In a .800-.900 contest, both heads using the same high lift valvejob, the Race port gets to a point of being 25-30 better, and more friendly to 500+ inch engines. I have some 2.040 and 2.095 versions of the Race port that we put on Super Stock apps that go pretty good with the small valves. With no rules, and most usable camshafts, the Street heads are the better economical choice for anything less than 500 inches, and don't require nearly as much manifold work. Straight-on lifters and rockers, and a reasonable port match will work.
The chamber options and exhaust port options are available with either intake port. We have done some Street intakes with really small chambers and Race exhaust ports that are really good and avoid the major manifold work. The neat thing about the Pro Port deal is we can mix and match programs and create stuff to fit a specific intention, rather than a one size fits all situation.
