You diesel folks may already know.
Less than 2 yrs ago I came across article in boating mag about new Penta. Claimed to eliminate ping/knock, smell, etc and cost was ok compared to existing diesels. They were using marine apps only initially but is probably getting close to time for ground vehicles.
I bring this up because I started looking at their Prevost info and was surprised they're powered mostly by Detroits. Nothing wrong with Detroits but if that class of rig was in my price range I'd want Volvo power. The performance claims of the new Penta would make the gas/diesel decision much harder.
Rexhall T-Rex Aerbus 36' May/2004 build
8.1 Vortec 5 spd Allison