1955 Chevy Build and Questions

[nogaroa4]

Well, I'll start with the questions...then move to pictures.

Some of you may remember I bought my truck about 2 years ago, and just finally got the motivation to get started. I was going to put the camaro front end on for the longest time, but then since my original frame was in good shape decided to go with the TCI Front Suspension.

I didn't get any instructions with the front end, and have been hearing mixed stories on how to install the front end. I forgot to mark where the original axle was on the frame. Looking at what other instructions online, I saw that Heidts recommends measuring 20-7/8" back from where the front spring mount is located.
Is that the larger of the holes on the front frame section?

Can I keep the original cross member or does that have to be removed? I wanted to keep it just to keep the frame stiffer....

Here are the pictures, any help is appreciated.