LA Block/Magnum Heads
You can put an LA cam in a magnum block, but why would you? There is no advantage to using a FTH cam in a hydraulic roller block, only disadvantage. The profile of a hydraulic roller is vastly superior to that of the flat tappet, no worries of rolling a lobe on roller cam, no worries of high zinc oil and they run cooler and have less friction. Stick with the roller!!!