Pick up gap is the gap between nubs on the fly wheel and the pick up coil. It should be about .020 or use a thin business card if you don't have feeler gauges.
Toomey has options for the T5's you run now:
http://www.toomey.com/index.php?option=com_virtuemart&page=shop.browse&category_id=4&Itemid=3&vmcchk=1&Itemid=3
If you seriously run the Pro Circuits, get the USFS approved silencers and keep them freshly packed at all times.
Best option IMO, call Cascade and get CPI's with their approved silencers.
CRC electrical/contact cleaner. Then double check the pick up gap. From there make sure the factory rubber seal is in decent shape. If not get another or maybe try greasing yours. RTV works but is a pain in the dick to clean up off that sealing surface.
Well doing the rough math on that and not knowing the piston type or gasket thicknesses, I'd say that motor is 10.5-11:1 compression. If it's burning the C12 run it. Touch of timing and I'd bet that motor prefers it.
Find old used ones from pre 2005ish. Or buy them raw and have your own chrome done and with a little shimming they fit. DO NOT PAY FOR HIS CHROME.
On another note: Rocket, CPI, Sniper, hand coned LED's FTW!
Milling is ok... But having the head rechambered would be far more ideal. It actually creates a new combustion chamber with a better shape and squish band.
You could even send your spare head to Driveline and have it machined to accept domes.
Had some trouble with my last guy getting my frame done and have been hoping to find someone in Michigan who deals with ATV's specifically. Not just a Joe Schmoe Fab guy. I came accross Southside Motorsports out of Port Huron Michigan and know they have done a few cool builds. Just curious if anyone has any real world experience with them?
You have made up your mind. Just put them on. FYI, the only people who are super positive about riding on 450 shocks or shocks from other ATV's are the same people going from stock Junkers to whatever they can find. Obviously just about anything might feel like a better ride. But doesn't mean it's near as good as a properly set up shock.