One of my customers has a Hyster H-200E forkift that is powered by a 305E V-6.It is running 2 walker straight through 2-1/2 inch industrial mufflers.It also is running the larger 401,432,478 V-6.. 2-3/4" V-band clamp type exhaust manifolds.It sounds great,almost as good as the Toro-Flow in the 1970 HG7500 oil delivery truck I drove in the 1980's. grin