Take the mufflers off.Measure the inside diameter of the muffler.Go down to NAPA or an auto parts store.Purchase two freezeplugs the size of your muffler-it should be ruffley 1-3/4" .Knock them into the front or of the muffler

.Then drill a hole in the center of each one.Install and test run.If too quite take them off and ream out the plugs with a porting tool or drill out with a bigger drill bit.It's cheap and worth a shot.
