My first mod was to put a SDC 80 type carb on it. It will not draw enough fuel with that carb and I caution against it. Here's what I did.
*Origional WGA carb but I moved the pump pulse line to be centered over the diaphram for a stronger pump action.
*Put the choke on a servo to force it to draw max fuel at max rpm. I run the choke to be slightly closed so it draws max fuel at WOT.
*Carved some pieces of aluminum to fit into the reed cage and create a better fuel flow. There's 2.25 oz of aluminum in there. The two larger pieces ride on the crank case and cannot drop into the crank path. The side wedges are locked in by the two larger ones. They clear the crank by about .010"
*The blocks almost touch the reeds at the base and flair to about 1/4" away from where they open. Any closer and power drops from lack of flow volume size.
* Retard the spark about 4 degrees on CH or 2mm with the Falcon. Don't ask me why it works but it does. The CH gives about 150 more rpm, again don't know why.
* 3" drop headers made from AI SS parts. KS KS86 canns at 8 3/4" length from flange to start of cann body, and also Bud Bottle muffs. The Bud bottles are good for 100 more rpm.
*7200+ rpm on a 27x10 Xoar. With absolutely 0 issues.
*It takes about a day and a half to carve the reed block stuffers and worth every minute.
* Fuel consumption went up from 12oz per 14 minute flight to 18 oz per 12 minute flight. I can run it rich enough to 4 cycle all around the sky without a burble. But of course it's tuned to run normaly. 4 cycle on down lines, clean in level flight.
*Also I tossed the head gasket to get the lower ring to ride higher in the jug. (Hope the new owners fix that little problem eventualy, ( the back intake port is too high)).