Need advice.. Changing from leaf to trailing arms.

[funkytechmonkey]

My suspension from porterbuilt should be here tomorrow, so I am pretty excited about getting this truck back together. Now this is my first truck build and I truly have no clue what I am doing so any advice would be great. And please dont knock me for such a noob question.

Here are a few questions I have.

I would like to keep the rear end I have but change the gears. How are the trailing arms going to mount to the axel? How do I align the rear end?

I am doing a mild notch and want to make sure I cut and mount it in the right spot. The rearend is not going to be mounted up so are there measurement I can go off for the cuts? This may be a question for porterbuilt.

Since I am changing from leaf to trailing arms I have already removed the leaf mounts and crossmember. I have a bare frame. But I am curious about this crossmember. Does the leaf spring crossmember with the big red arror in the middle need to be removed?