There is a 6 bolt bellhousing (not mine) listed on ebay for collection in Bordon, Hants:
http://cgi.ebay.co.uk/FORD-289-302-T5-A ... 3cb4e53041
The advert refers to a T5 gearbox (which would require an adaptor) but it actually fits a wide-ratio Toploader gearbox (HEH-B) as per the Mk II Tiger . It will also fit the stock Mk I Tiger (HEH-E) close-ratio Toploader with a little modification. See Brian Postle's article:
http://www.sunbeamtiger.co.uk/tech%20tips/engine.htm