I am using a factory vaccuum solenoid switch (its located behind the washer bottle in an EF/EL), mines sitting near the washer bottle in my engine bay if you look

The frequency switch is set on the low to high mode, I am using the normally closed side to hold long runners for low down power/torque it then monitors the RPM signal and at the point I have set (around 3,800rpm) it switches to short runners for top end power (effectively cuts power to the solenoid).

the switch can do something on NO (normally open) and NC (normally closed), I am thinking of adding a LED indicator light to the NO so I can see when the switch frequency i.e. rpm switching is actually happening.

Hope that makes sense and explains a few things

I haven't really looked that closely into it yet, but it is still vaccum that's controlling the actual switching of the runners ?
Like you can manually push up rod at the front of the manifold causing it to switch, but it's still vaccum that's powering that movement isnt it ?

What I'm thinking is to eliminate vaccum all together in the switching process and have a solnoid type arrangement physically push that rod...

Oh ok, thats a nifty idea, I might try an XF boot release solenoid as a test :0)

It's probably not so much an issue for you, but my BBM switching is playing up intermittantly and you can see from this dyno chart what it's doing to performance. If I can inpedendantly make it snap hard instead of what ever it's doing now I'm sure I'll be better off...

I've seen a lot of EF-EL dyno graphs now that have the dip where the BBM switches, if someone gets a better system for switching working I'm sure there will be many (myself included) interested!

I will be having a play on a dyno early next month, will see what I can rig up in relation to a solenoid switch and see what the result is.