SR20DET to GM(Auto) transmission adapter

[240Z TwinTurbo]

I am currently working on a transmission adapter to mate any GM/Olds transmission to the RWD SR20DET. However, I need to verify a dimension if someone can help. I need the distance from the back of the block to the crank. Basically, the block surface where the transmission mounts to the crank surface where the flexplate/flywheel mounts. I should have the adapter done by the beginning of December. This is not one of those projects that will go nowhere. I have sucessfully done this adapter system for my 240Z datsun mating a powerglide transmission to my 280zxt motor. Results were very good going from 11.06@129 to 10.6@134 with only a transmission swap. Here is a pic of the transmission adapter on my Z. I have sourced this project out through a company that specializes in transmission adapters. These will probably be sold by myself and Enjuku Racing.