shower to tub conversion

I am thinking about converting my 32" shower into a raised 55" tub (older model, could have had clawfeet but now sitting on blocks). The tub is currently in an old house and I would have to remove it from said home. I have enough room to place the tub after demo to the cabinets beside the shower stall. I was wondering what all would be needed to do this conversion.
I have been told two different stories regarding the drain. First one would be that the concrete would need to be drilled into and removed to move the location of the drain and place it at angle to ensure proper drainage.
The second story is that since it is a raised tub instead of a drop in that it would be okay to leave the drain where it is and run the plumbing with a 45 angle for drainage.
I am also wondering how I would have the tub elevated without having clawfeet attached, if at all possible. Would building a platform be appropriate or just a waste of time and money?
Any input would be greatly appreciated! Please note that this would be a DYI project.

The drain goes under the tub waste and overflow.
That my mean breaking concrete to move the drain.
The trap arm length to vent can be
1.5" pipe, 42"
2.0" pipe, 60"

We replace tubs with shower all the time. Most time we can use the same plumbing waste line. Here in Canada a 1.5" drain line is ok for a shower.

Often the hardest part is cutting back the old copper drain lines in high rise multi family type scenarios. A dremel and and some paietence or a pipe shooter can help loads.

We tend to use a linear drain across the back wall for these installs. JW