you can make your own spacer if you go to the auto parts store and buy yourself some gasket making sheets they come in a 12' x 12' sheet and about 1/8" thick , take this and cut out a gasket between the engine and muffler and wola ! ..... instant spacer , you can even double up on it which would give you a quarter inch more clearance then what you have, this would also serve as a good seal for the muffler connection to the engine and limit any possible leaks from fuel keeping your engine compartment cleaner as well, just make sure you use locktite on your muffler screws and you should be fine