Where can I buy Olds Offenhauser water neck?

Having a hard time finding one, mounting holes are 3 3/4in apart, 45degree. Been looking for awhile. Does anyone know of a different make that might work? Any help much appreciated, thanks!

 

There's one on ebay for a 57/58 J2

 

what year?

 

I'm looking for one specifically made for an aluminum Offenhauser intake, 57-58, 3 carb. They are different from J-2, and from what I know, made only for these intakes