Technical Help with buick nailhead st400 yoke

Can anyone tell me which yoke will fit this transmission tailpiece. I bought it off a guy and I am confused if this one is for a standard turbo 400 yolk, or the Buick yolk for this year trans. I have to make a driveshaft. Anyone been down this road? Thx!

 

they used a smaller OD yoke on the early ones like that. you probably want to get a later tail housing from a chevy (70s-80s) and a normal TH400 yoke with 1.89" OD. Measure how big that one is first, though.

 

Do you know if the bolt pattern is the same? I'd hate to relocate the mount.

 

should all be the same, except the size of the bushing and seal.