So uN ... my thoughts are NOT to do many mods to the frame/chassis. Just setting the motor way-back. From what I know .. the floor and roof-pillars etc ...are way over-built by Chrysler so the stiffness of the chassis should not be a problem...

There was a '90-something Caravan with a 360 in it ... IN a stock-type location(but with some major firewall mods) .. but HOW he worked out a decent oil pan and exhaust-system had to have been a horror-show.

The cops ? ... why would there be a potential issue there? No obstruction-of-vision issues.(the whole van is mostly glass). It would be driven from the mid-seats ...not from the rear seats. And there would be LESS tip-of-the-frontend to driver location than in most typical muscle-cars and way-WAY less than a C-body !

So you seem quite familiar with drag-strip-tech ... ?