Mark thanks for the suggestion. I found that I can get a housing here in the U.S. from a 300ZX which is a Non World Class box and have it machined for my use behind a mustang Z-spec box which has same ratios as the Cosworth Sierra.

I will change out the over drive to a more useable .73, .78 or .8 and make adaptor to use speedometer gear in the new location.

Great thing is the 300zx uses a ford shifter so my nice MGW mustang shifter.

For reference the Standard mustang shifter location is around 2 inches / 50 mm forward over the stock t9 position in my Xr.