AN vs NPT info?

Can someone direct me to where online I can learn about AN and NPT systems?

I need to know how the two systems relate. I will be doing a remote elec water pump and I'm confused about what size water hoses are compatible with what size AN and what size NPT fittings I need to use. There's no 'kit' for my application so I need to design it, which means first I have to know what I'm doing.

Specifically at the moment I'm trying to figure out what size NPT fitting I need to put in the block/heads to accept a -12AN fitting and appropriate hose and not have a restriction from reducers that don't flow enough. My front cover has ears that block off the inlet ports so I need to work from there backwards I think. Meziere suggested -12 as the size that's right for my cooling needs but his block adapter for a big block won't fit my 1stgen hemi so I'll have to fab something up. I was thinking either drill and tap the ears for NPT and then the AN fit to that...or maybe use weld in bungs and put a -12AN male fitting right on the aluminum cover. Or do i even NEED AN fittings? can I run regular hose to barb fittings? I like the look and security of braided line but I'm open to getting the job done easier/cheaper too.

Thanks

For the heads I have a set of plates with 1/2NPT female, I'm not sure that's going to provide enough flow.