truck boot

There are several ways. One is to go to a place that sells camper tops and buy the "accordian" pinch molding, sold by the foot.

I have fabricated boots quite a bit cheaper by using scrap vinyl. Fold it , form a rectangle (or whatever shape opening you cut), bead the seam with silicone and screw it around the perimeter, cover with custom trim panels. So far no reliability or leak issues but the install quality is the reason for that.

Perhaps others will post thier methods as well.

Good luck with the project and post pics when done.

Thanks again, sorry for the delay in getting back to you.  The truck is actually not mine.  I'm doing a buddy's system.  Anyway, the truck is a 98 regular cab.  I'm just about finished with the inclosure.  It's a daul throated horn design.  It will be loaded with two MTX thunder T8510's.  Each seal chamber has just under a cube and a half.  Then thoats out two about 7 L feet of horn.  I built one for a guy around xmas time and had 12'...freaking unreal..  Anyway, the throat combines both combination chamers and dumps out the very center of the box right in the center.  Looks like about 12 inches X 16".  The lastone I did was so dang loud so I wonder if having this thing point through the cab at their backs may be to loud???ha ha  I hope so.. Taste my shoe...HAanyway, again thanks!  I appreciate the info.  I'll try and get some pics posted here before I glass the box today.  Camera is acting up  so well see. 

Never have had so much fun doing something that makes "some" people really happy.    I love building the loudest hardest hitting monster around. Cya

There must be quite a few but heres a link to one. Scroll to the bottom when you get to the site and there is a pic of it and pricing.  Good Luck.

http://www.pickupspecialties.com/Camper_shell_parts.htm