Andy,
The K&B 40 will work fine but you need to get the right venture around a 0.275 with ST NVA through the venture (Jim Lee or Randy Smith has them see vendor's corner). They like 10% nitro and 24% total oil (50/50 ok). Don't over prop it, a 10 1/2 to 10 3/4" x 5 prop works fine. Likes to run rich 2 cycle (almost a 4 cycle). Ship should be around 52 - 56" around 48 -50 oz ish. Mine works fine with a tongue muffler.
Best, DennisT