Sharpie said;
If you run LA heads on a Magnum engine, you will need to drill the block for oil to the head. This passage is not drilled on Magnum engines.
Keep it simple and use Magnum heads and a Hyd. roller cam since you are allready set up for it. You can get mello grinds via request to Comp Cams, Crane cams, huges engines, etc.........
Excellent Idea IMO, but probably more cam than you need for what you describe.
Though I'd skip the Edelbrock heads and just spend some of that money on preping the Magnum head at best and most. The OE head can deliever the power your asking for without porting. The smaller valve size of the OE head will keep velocity up and quick. This will provide a snappier throttle.
No way, no how, unless you retard the heck out of the timing, at which point you'll dial out any performance.
Pick one and run it. IF it were me, I'd run LA style stuff up front. Timing chain doesn't matter. There the same.