See Feb.2000 High Perf.Pontiac.They have an article on a 1966 Grand Prix with a 455 and a borg warner Gm T-56 six speed adapted into it.It say's it was installed with a Lakewood blowproof bellhousing and block saver plate.
You might try searching their web site I believe it's
www.highperformancepontiac.com
If you can't find the article I could try to scan it and e-mail it if you like
[email protected]
smokem if you got em