Magnum heads on LA block H.p increase

Also iam a little confused reading on the swap from La heads to magnum everyone is saying to use AMC style lifters because the magnum heads oil up through the push rods, since i have a LA Roller 318 block with roller lifters already i can just reuse my current lifters? or should i use the magnum roller lifters from the magnum block?

And i been reading that some had issues with the push rod hole in the magnum heads they had to open them up a bit.