I have a totaled 2007 f350 lariat outlaw and I want to switch it over to a extended cab and can't find anything on it does anyone know how the cab mounts would need to be modified and or relocated for this to work

 

Not sure what you mean, your picture is of an extra cab.
We generally call that a Super cab.

 

If your talking about switching it to a crew cab, that might just be short of impossible. Pretty sure the frame is longer vs a extended cab with a short bed.

 

Not very good pictures or explanation of what OP has and wants to do. If both trucks are accessible, grab a tape measure see how they both fit. That is what I thought at first glance, but the picture shows a crew cab, it has 2 door handles on that side. Back door handle is right behind the tarp grommet, and the dark line below the grommet is a shadow of a strap, not the edge of the door.
And I am not familiar with an "Outlaw" Edition, but I Googled it and crew cabs are all that came up.
Sounds like he has a crew cab and wants to use a Super Cab on it. And I believe the body mounts will be in the wrong place, so you may have to weld in new ones. And as mentioned that will put the bed off spot. Sounds like more hassle than benefit. Just find another crew cab body.

 

I will be building a custom bed not a oem style bed so the cab is what the issue will be

 

I would be building a custom bed for the truck because I have no need for a crew cab so I would like the extended cab/super cab for the extra leg room versus a single cab

 

Actually, you'll have room for a regular long bed.


As far as Cab mount locations, you figure out what needs to be done with a measuring tape. You do whatever the job requires.