LA Cam into Magnum?

I thought the lifter bores were at a different angle in the magnum block...

No there the same angle in all factory production small blocks. Only some race blocks have a different lifter angle.

Jon if your planning on running the stock fuel injection that means you will be running the computer and they are real touchy to cam grinds so I doubt a cam ground for an LA will run right unless it's specifically ground to work with the fuel injection. Before you did that you'd be much better off staying with the stock magnum roller cam. They also sell higher perf. magnum roller cams and you can reuse your original lifters so they don't cost much more than a cam kit for a LA.