Well, we've never done it this way. Of course I have to answer to a customer, you only have yourself to answer to. I'd worry about breaking something this way; the blasted dash pads and supports NEVER want to line up or lay down right when the job is done the right way. However,I must admit I find this way to be a bit intriguing, intriguing enough to copy as a possibility for the next heater core we have to do. I think you will find it hard to work in the space allotted, but hey...if it were me, and my car...I'd try it. Nothing ventured, nothing gained...

Chris