Don't know the answer to your question, but having a GMC Savana with a 2.8 Onan, it makes a lot of noise and vibration when running. If I didn't have a generator and wanted to run A/C, I'd just buy a portable unit. Actually I did buy a Honda as well.
2008 GMC 3500 Quigley Weldtec 4x4 Savana SMB
2006 BMW HP2 Enduro-Sold