Search like this...
Forum to search: SVT Headquarters
Keyword search terms: "mach 1" [use the quotes or you'll get every post with the number 1 in it as well as every post with the word mach]
Date range: newer than 1 year
That gave me 42 hits, one of which was...
http://www.focaljet.com/ubbthreads/showf...#Post2416816263
I also posted a similar write-up in exterior mods. Basically, there's some trimming and cutting (of the lip) required. It attaches with bolts if you want to drill or self tapping screws if you don't. It takes some patience to line things up right, clamp in place, screw/bolt, rinse and repeat.
Good luck (searching, that is).