Buick to ????? Bell Housing I.D. Help Needed

I picked up this aluminum bell housing that fits on a "big block" (364/401/425) Buick nailhead, but I haven't been able to find out what tranny mounts to it. The only marking on it is either "HD75" or "HO75" which is cast in. There's a (crappy) pic below with dimensions. Any help would be much appreciated.

-Bob

 

Looks like Ford Top-loader.

 

I will second the motion,,,,

Ford toploader

 

There looks to be enough material there to drill a GM pattern on there too.

 

Thanks a lot for the info !!

-Bob