Two Questions, one thread

So I’m really enjoying my 1973 Newport with the 400 big block.

Two questions, I’ve searched but didn’t find any.

What spark plug is suggested and does the electronic distributor need its cap replaced or is it good for a long time? (My first distributor car)

What is the expected MPGs out of these cars? I know it’s not gonna be a Prius but I would like to make sure it’s performing as expected.
Author: prd2bdf