OK I am confused about my trans

[mrsmothers]

I have a 1971 chevy long bed that has a 3 on the tree. Well had a three on the tree as of today its in the trash.

I have a muncie 4 speed to put in it first off I have no clue what type of muncie I have. I the numbers on it are 3901131 gm 30 there is also 65452 and h218 the shift knob has L 123 R on it.

Next question how do I put it in, where do I drill the hole in the floor will the drive shaft work, will the bell houseing work is there a place that has step by step pictures.

I am trying to get this in this weekend so any help woult be great