Ported 596s

As long as your Magnum block is drilled for oiling to the heads... yes.
You can type in LA heads on Magnum blocks in the search box in the upper right hand corner of your FABO page for a wealth of info in that area.

You will also have to run the LA style rockers of coarse..
If you're using a hyd roller with the OEM Magnum roller lifters, will have to use custom pushrods to fit your LA rockers and short enough to run with the longer Mag lifters.
I have not actually done this before.. I'm just pointing out the obvious..
I'm sure someone here on FABO will be willing to steer you the right direction..

Thanks