Hey Tom,
Moving pretty fast!It's looking great.
Quick Note - IDOhave a build video, but it won't be done till tomorrow. Then I'll have it online. It will make it easy to put together for even the most novice.(Ithink!Feedback appreciated).
Yeah, the firewall was moved back for that "other"engine...
I'm with ya, Ihate to cut out the cowl too, but that's the one thing with the JCon this plane, is that the cooling head is go close to the prop hub, that you are going to HAVEto cut that out, ORif you get a machine shop to cut you an extender somehow?Not sure if that would work (if the thread on the engine shaft would be long enough or not?)
IFYou do deicde to just use the hub where it is on the JC(this will mean moving the engine up about 20mm), I would cut blocks of 1/4"plywood. See my horrible digital drawing!

Start with 1 1/4"x1 1/4", then 1x1, then 3/4x3/4 for example.This will give it a firm seat on the firewall, and use a smaller amount of wood. I'm not sure exactly how many you'll need but this is the idea.
For those of you keeping an eye on the thread let me know if you have any questions. Also - Ihave an mx2 that will work with the JC28cc engine WITHOUTmodification to the firewall. Green and Red Schemes on that one