G'Day Tony,
It is law here to box ALL of our chassis rails as part of registration.
The hardest part is making sure that you plan well ahead to ensure that you have all your fuel/brake lines, electrical wiring and captive bolts in place BEFORE boxing the chassis rails.
It's really hard to get all this sorted once the rails are boxed.
Once that is done, the boxing is quite a straight forward process.
A real handy tip is to use strips of cardboard cut out to the exact shape of the frame rail, trace them onto your sheet steel and then cut out the boxing plates to the right shape.
Good luck....Doc.
