Underbody sound deadening - older truck
Looking for the best option for underbody sound deadening. I have an old 4runner and the inside is stripped and linexed, so a mat/material that lays down won't work. I can put something inside the rear wheel wells, inside of the front wheel wells, and on the firewall behind the dash as it is all torn apart already. The only other place I can put sound deadening is on the underbody, which wouldn't be too bad b/c there isn't much under there other than the tranny and transfer case.
I'm not looking for something that is going to be a silent ride by any means, but reducing in cabin noise would be great. What are your thoughts for the best options on a project like this? I am not just talking about doing it, this project will happen and I can post pics/progress if you all want it.