Mopar Muscle Association UK

So I am going to get a spare 904 to rebuild at my leisure for my chally. I know it's a bit of anorak behaviour here what chance have I got of getting a box close to the build date of mine (9th june '71) obviously the box was probably built early '71 Any idea's guys

I by accident found my trans number on the 904 when I took it out for the third time this year, and I am matching numbers for the trans (not the engine)
I think you would just have to look at the stamped numbers of any second hand box and try to find one close to yours. I am sure Duncan will know more about date codes and the like.