Baggin a suv question

So I'm dropping a 4runner body on m single cab frame and my question is what other have done with the rear floor of a suv. I was planning on just cutting it out and raising it. If I do tht should I brace the area where I'm cutting out so the rear doesn't buckle or will it be strong enough without bracing. Any tips are appreciated

I'm building an 88 4 runner on what used to be an 86 Xcab frame. Here's how I did the rear.

It's built up with 1" square and 1/2" square tubing.



And here is a 99 blazer I'm doing. This is also built up with square tubing.

Here's how I did the front portion on the 4 runner