To me the short block is basically the same there's obvious little differences, but it's mainly the head package that divides LA vs Magnum's. Stock 1.88 la heads vs magnum heads the magnum heads seems to make 20-30 hp over a similar done LA and pull out strong peak torque numbers.
If you have a running 318 or 360 slapping on a set of wrecking yard magnum heads would be a cheap upgrade, but now we have cheap aftermarket heads like SM make a better up grade for a little more $$$.
