I've spent the past hour searching here and on the net, but can't find anything, so forgive me with this has been covered, but...
I thought that there was only 1 style of 5 bolt patterns for T3 Turbine Housings, but I now have a .48ar Turbine Housing from a T-bird Turbocoupe, and a swing valve assembly off of ebay, and the Housing is about a centimeter shorter then the swing valve assembly? wtf?

 

there is a 4 bolt and 5 bolt. the thunderbird uses the 5bolt so any bigger kit you will use for the turbo the downpipe wont fit.

cheapturbo.com has the 5 bolt flange so you can go external. you just weld the flapper shut and make a custom dp utilizing that flange.

hope that helps