I've done the magnum head > LA bottom end swap a couple of times. Both times with EQ heads.
With a small (what used to be called) "RV" cam, really woke up the engine beyond what a similar build with the same cam and stock LA heads did
A little better ports, a little larger valves. smaller valve stems, and a closed chamber make them what they are. You would have to work on a LA head to make it equal. (like a #920 or a #302)