Here's a little "how-to" on my header/canister install on the 78" Extreme Flight Extra. We had sold off the 40 twin that I had been running all season so I'm breaking in a new 40 twin with the rear dump canister on a 20x8. Turning about 7100 (on the ground) with both stock muffs and the canister with the same power and response. Sound is incredible and can't get much quieter unless it's not running!! In a few gallons I'll bolt another 21x8 laminated prop back on and it'll be business as usual.
Here'a little step by step on what I had to do on this plane:
Since the header would block the canister tunnel access I started from the back to front. Slid canister in place and then fit in the canister mount. Had to relieve a little material out so everything would fit nice and easy. After drilling and hardening the holes, screwed the mount into place.
Upfront I prepared the coupler by putting the clamps in place. I've found that it's easier to do this before hand. Whenever I mount a canister I always drill a small hole through the coupler and header or canister, then put a small screw in. The screw stops everything from rotating when in place and is further secured by the spring each spring clamp so it'll never come out unless you take it out.
Moving on to the header, you may need to remove your idle screw. I start by threading the rear bolt into the cylinder and gasket (through the spacers.) MAKE SURE YOU HAVE ALL SPACERS AND GASKETS ALIGNED and ensure you put a gasket between the spacers as well. Use red loctite so you won’t need to retighten the bolts later! Leave enough length in the bolt so you can slide the open end of the flange into place. Slide the flange into place then insert the front bolt with red loctite as well. Tighten both bolts with the included low clearance allen wrench and repeat on the other side.
Due to the right thrust in the engine box, the exit on the header points slightly to one side. This is not a big deal at all as you ultimately control where the exit on the canister is centered. Finished results are clean and more importantly QUIET.
Only thing not in the pics is teflon wrap. Make sure and wrap the ends of the coupler with teflon tape (plumbers tape) to prevent unnecessary leaks inside your cowl. Hope that helps and good luck!! http://www.GiantScaleNews.com/forums/images/smilies/198.gif