pushrods for mag heads on LA

I have a 1976 318.

I have a set of 2000 Magnum heads (and exhausts).

I have a set of AMC style lifters.

What length pushrods do I need? Stock LA?

Assuming stock bore, how much compression increase will the Mag heads give me?

This could be a home for my 272/454 cam, and the 1.6 rockers should make it closer to 484 lift.

Does this sound more sane than the last plan?