drag v-drive whirl a way spacer

So, many of us drag guys use a clutch instead of shifting the whirl a way in and out of gear to leave.
We put a spacer between the rear drive dog and the bearing in the rear of the housing.
Anyone know the dimensions of that spacer off hand? I use the alcohol style whirl a way housing... so mine may not be the same as a regular casale housing converted.
Thanks
Wags

drag v-drive whirl a way spacer