Hydraboost question
 

I recently got a hydraboost from a junkyard for my 69. My question is this, since there was no master cylinder on it, what code do I look up for the braking system at the parts store. It asks about JB5, JD5, JD7 etc. I don't know which I should look for. BTW, it came from a 82 3/4 Sub. I don't remember if it was 2WD or 4WD.