no mufler on the one i had, they are usually a little faster the non turbo injection pump has a different part # just because the fuel is adjusted a little higher, when the turbos went on it was to kill the smoke ONLY and the fuel was a little lowered also, NOW there are many out there that may have had the turbo put on and the old injection pump left alone like i did on mine and she is a runner, and someone in the past may have juiced up the timing on existing turbos , its been done here at the armory in the past, so dont be surprised to find many that are runners, but thats the basic scoop, Mine was like following a forest fire, when i started it with the turbo on it i was totaly amazed, no smoke, had to see the before and after to belive it, even though i already new it, just amazing...so smoke is really the only difference.and maybe a little more fuel...Randy