Big Block/A-518

And the stock bell is cut off? Got a link?

Yes you cut off the stock bell housing. It can be done with a cut off wheel and I've even seen it done with a drill (what a hack job though) but having a machine shop do it with an end mill or something is a lot neater.

Check page 3

http://racewithjw.com/JW-08-Catalog.pdf

Not everything is listed in that PDF though so you are better off just calling them.

http://www.racewithjw.com/index.php