I recently bought a second truck for my bread route, it's an e350 econloline with rear heat that blows really hot/strong, I was thinking of laying down a plywood floor and venting the rear heat under the plywood and sealing the edges to trap heat under there. my primary truck is a 3500 series with a grumman style box built in back, theres a spot on the wooden floor in there that gets hot from the exhaust and when I leave a box there for a little while the bread heats up nice and customers love it. was wondering if anyone ever tried something similar?