727 speedometer housing

I have a pretty bad leak coming from the speedo housing on my 727. I bought the trans as a low mile rebuild. I installed it over a year ago when doing a slant 6 to V8 swap. The speedometer hasn't worked since. I ordered the correct 36 tooth red gear to match the 3.55 gears and a seal kit. It had a 28 tooth blue gear in it.

My problem is that the housing isn't marked to show the proper way to clock it. It only has 21/25 on it. Do I need a different housing or is this one fine?