I am curious, are your VT365 fans always running? My VT365 fan is electronically activated and only comes on at approx 200 Deg engine temp. Once the fan cycles on it drops the engine temp down to approx. 180 Deg and then the fan disengages again. Yes, the fan is quite load when it is on but otherwise it is not spinning and everything is quite.
In lieu of an electric fan you may want to look into a two-speed or variable speed fan for the VT365. This would allow the fan to run at lower speeds when maximum cooling is not required; lower fan speeds equals less noise. Check out (hortonww.com) as they may have a direct bolt on fan clutch that will quite things down without having to redesign your electrical system to run an electric fan.
If you are dead set on an electric fan, or you just want more information, check out
www.electricfanengineering.com. I have been researching large over the road electric fans for a project I am working on and this is the only place I have found that specializes in large vehicle fans.