There is something to be said about those old monster gasoline bus and fire truck engines. Those old SEAGRAVE and AMERICAN LaFRANCE V12's were sweet with a sound like no other. The fire apparatus around here(Milwaukee and midwest) mostly had WAUKESHA L6 engines in apparatus when they had gasoline engines in them along with many MACK apparatus. The HS engines were mostly on the west coast but I would imagine some made it east of the Rockies. I bet that was a sight to see and hear when those huge engines backfired like that. Hope they didn't "create" business.
There are fairly new BLUEBIRD VISION propane powered skoolies with that FORD V10 that serve the school district in the small city of Waukesha. They are fast and have a nice exhaust note and tranny whine from the 6 speed automatic. The first time I got along side of one and didn't know that company bought them. I couldn't believe how quiet they were since I was used to the diesel sound in those.