The factory assembly manual does call for undercoating under the fenders and cab of these trucks. I was suprised to see black paint in pretty good condition in the few spots where it remained under my front fenders. I know a lot of folks these days use bed liner like undercoating. I believe the theory is that the rubberized bed liner will not seperate like old school undercoating and also acts as a sound deadener. I too have heard that undercoating can trap water, but this can only happen if the undercoating is not properly and fully bonded to the surface. Some of the rod guys glue dense foam pads under the fenders, but this is more to stop paint damage on the exterior from rock damage than to prevent rust. Just a good coat of expoxy primer and paint will do fine as long as dirt and trapped water are not allowed to build up under fenders.


1950 Chevy 3100
261, 4 speed
Purchased 1977

1964 Pontiac Lemans Convert