Why not keep the heads? Magnum heads outflow almost every LA head by a fair margain.
Also, if you plan to use headers with the "Magnum" series block, take note of the extra casting nubs on the sides of the block just below the decks. These interfere with the header pipes and don't allow the flanges to sit flush against the heads. Maybe mock it up out of the vehicle?
I don't have a magnum engine, my 360 is one of the last years of the LA block and I don't know if it has the correct oiling setup 4 Magnum heads. Plus I'm not familiar with Magnum heads or pedestal rockers which I know wouldn't be too difficult to figure out. I guess I'm just more comfortable using head I'm more familiar with and that have more intake options. I'm not sure but I think I can pick up a pair of cheap 452 heads and get them cleaned up and some minor port work done cheaper then I can buy a set of Magnum heads. I know the Magnum heads have issues with cracking and I'm more confident that I can find a set of used older heads that don't have cracks. The only thing that I'm somewhat worried about is the exhaust ports in my current heads being in a different position then the older heads which might make finding headers that fit in my truck more difficult
