bob, that is correct. I believe the LX (shorter gold muffler) will fit perfectly with the toni extension kit only. acyually if dub offered a 1/4 '' spacer the 90L would fit the minnow without problems. my spacers consist of 3 pieces. just 1 additional 1/2'' spacer. i broke the engine in on a 11x5 rich at approx. 14,800. I ran only 2 tanks of fuel though. it would peak approx 15,400. I have not ran it with the preferred 12x6 benchmark prop that you previously reccomended.