Has anyone use a oil cooler as the heater core? I am thinking about using the oil cooler, more mounting options, thinner , lighter.....I was going to mount it in the middle like everyone else that use johns system. I am going to lowes and buy a large vacuum adapters and use it for the ducting. I am going to mount 3 small fans, one on the bottom that can be switched on for defrost and the other two on the top which I will use ducting to direct the heat to the feet. I don't want the extra heat blowing under my radio stack. Any thoughts on my installation before I buy the parts?