if i build a BUDGET 360.... LA Vs Magnum 5.9

If rebuilding it matter less, if want to go hydraulic roller then last few years of LA or all magnum or need to buy retro fit lifters for older ones, if not, it don't matter, magnum generally don't have oiling hole for LA rockers so if you want to use LA heads then you need the right aftermarket rockers. The roller LA 360 is the most versatile choice but any of the can be made to work.

As for heads it's really not worth messing with stock heads, stock magnums are know to be able to make 400 + hp as is, more if some porting is done but are known to probably be cracked which generally ain't a problem for a down and dirty build but don't really want to invest too much money into them.
1.88 valve LA heads need some work to get into the 400 hp, most feel there better for all out porting and prefer there rocker gear but again can be made to work but generally better off going aftermarket especially if looking for 450 hp + and even if not better heads generally need less cam to make same hp.