I have never seen a race car (where the owner had a choice), run with a 6
port engine.
The 6 port works with high revs and a very complex tuned manifold.
Without the valving to transition between the RPM ranges, it will be a dog at
lower revs. Poor runner velocity and the like.
Save yourself a lot of pain and buy the 4 port. Simple manifolding, even
if you build it yourself.
All of the racing stuff works fine, if you want porting.
Look for 180-190 HP from the base engine with a big TB. If you really
need well over 200 at below 7,000 RPM buy the turbo now. Or learn to street
port. You will be surprised to find out that real airplane engines have
nothing close to their advertised HP. That 180 real dynoed HP of a rotary will
have you outrunning the real airplane engine powered stuff with the advertised
200 HP.
Lynn E. Hanover