670 hacman ?

[tx_swordguy]

I have been reading the 670 threads with interest and I know it is stated that the hacman mixture adjustment is not supposed to work on them. My understanding is it is related to the rave valves. My question is would it work on the engine when the rave valves are not operational (such as below the opening rpm)? In other words could you use the hacman in a cruise setting and have it richen up when you go full throttle for climb/take off when the rave valves are open? Or does it do the opposite and lean the full throttle condition too much? Just curious as to what actually happens
Mark

[Dusty]

The hacman and rave valves may be a problem,but the valves generally don't start to open until around 6400rpm?
You won't be operating in this range often, so fix them shut (20 thousands of an inch clearance)?
I believe the advantages of controlling mixture outweigh any gains from variable porting
There are a few 670's flying successfully ,maybe someone with firsthand knowledge could add to this.