I wanted to let you guys know I still have ideas swirling around in my head about how to make the first prototype - regardless of the type of valve I decide to use.

Since I'll be trying to replicate all the current .21 engine specs (mounting-wise, etc...), I'll just start out with something like a VG-30. There's a pull-start version, so it'll have the nub on the end of the rod journal to drive the supercharger valve (if I decide to go that route) and valvetrain. It also has a fully functioning induction valve and a very standard place to mount the carb if I decide to try supercharging. Most importantly, it's got a long enough stroke for the larger displacement thumper. If I can bore out the cylinder big enough to fit the FS40 sleeve, it'll just be that much easier. If not, I know a guy who could weld a machined cylinder to the crankcase easy enough.

Basically, it's just that much less stuff to design/engineer/prototype/test to get the very first working prototype. I'm sure this method will save lots of money and time.

With the racing season wrapping up this month, I should have a little more time to work on this.

The other day I thought of a variation on the slotted valve idea that would allow almost 2/3 of the valve's surface area to be fully open vs the current limitation of almost 1/2. It requires 2 sliding components per valve and offset sealing surfaces, so it would be much more complicated and expensive to produce... Probably never see the light of day, but it is an interesting concept to think about.