Well let’s see.

It looks like you are not running a header, but just the factory flange, so I think you are too short for even the APC 7.4X8.25 carbon.

I’d use a Macs #3521 15 degree fuse top header. Both header and pipe may need to be cut so that you don't end up with the coupling at the turn on the header and to get the 9 ½” distance from center of piston to the large diameter on the pipe apex (this is a reference length). But work your length down on your own since your pipe may be a bit different (start 1/2” longer). On your pipe the measured distance is where the big part starts to get small again (exhaust end),

Your pressure tap is not at the apex, this may give you problems with even fuel pressure throughout the operating range, only time will tell.

This header will let you run a 8oz. fuel tank (Sullivan #SS-8), when it’s running right it’ll suck that tank down in 3 minutes if you are running 30% nitro. Use real Du-Bro ¼” foam rubber under the whole tank bottom and smaller pads around the sides to keep it isolated. Don’t have the hold down strap too tight or the fuel will foam. I use a real OS bubble-less clunk. Another option is a bladder tank and you can hard mount it down. I’ve never needed a bladder tank. When you reach high rpm’s these two tank set-ups are a must.

Id bet that you have only a few threads engaging that prop nut on that small-thin sport prop. And if you modified that prop to get more threads, you’re lucky the engine didn’t come alive. Thankfully the tuned length was way too short for those props you listed.

When you go to the carbon you will need a “short shaft adaptor”
(Tru Turn part number TT-0141-A) is what you’ll need. Ream out the prop to fit the short shaft adapter. Turn the prop and hold the prop ream tool stationary for best hole concentricity than balance. Start reaming from the engine side of the prop. Take your time.


I hope you sealed the engine mount area with epoxy, the fuel will eventually eat away at the CA.

If not, remove the engine and use K-2r cleaner. Used in moderation can lift the surface oil. Use thin CA in the edges of the mounting holes and engine cut out to help keep the wood from crushing. Seal with epoxy when done. Check engine mount screws periodically for tightness.

I’m 51 and my eyes need extreme contrast from top to bottom so that I know what’s what. There’s not much time to decide on the right move to do at the speeds you are about to be traveling.

This is what it should sound like, this is an old clip seen here before. The poor guy had a devil of a time keeping it in the frame and was afraid to go past the fence LOL.
http://www.youtube.com/watch?v=5m0t925_elc

I hope info this helps.
Karl