Who has the fastest /6 here
your right... i never have... but have you ever ridden in a SS Hemi Dart?
i know its not a slant but the same principle applies... i know i can make more power with boost, or No2 but i like to challenge myself with building a good combo NA.
has nothing to do with if it makes the most power...
That's an admirable trait, but the problem is, you have chosen one of the worst possible engines to try to do that with. The narrow (small) bore center spacing of a /6 hamstrings all efforts to try to put decent size valves in the motor, and the fact that the ports were designed for a 170 (and, they were) doesn't help any. The only engine I can think of that is a poorer choice for trying to go fast, normally aspirated, is a 144/170/200/250 Ford 6, with the integrally-cast, intake manifold.
The "big" Ford 6 (240/300) has much larger valves, and can be fitted with Cleveland, welded-up, V8 cylinder heads (which have humongous valves,) if you don't like the stock head, and the 250/292 Chevy 6 is also another engine (which also has a 4" bore) and can accept large valves. It also can be fitted with the V8 cylinder heads, if you don't like the 6 head.
The /6 can, with forced induction, run toe-to-toe, with either of these brand X engines, because of it's unusually strong infrastructure which allows LARGE amounts of boost to be used without damage to the reciprocating assembly, with 500+ HP fairly easily attainable, as evidenced by Ryan's and Tom Wolfe's cars on FABO.
But, because of the lack of a really good breathing head (and, I'm not sure that's ever going to be possible, due to the close bore center spacing of the /6 block,) trying to build a normally aspirated /6 that has specific output numbers approaching 2 HP per cubic inch, or even 1.5, is like trying to run a marathon with your mouth sealed with a piece of duct tape.
Mark's car still amazes me... It's a rocket, for what it is!!! Love to watch it run...