maunal vs. power steering with TTI headers

my car came with stock manifolds with manual steering, 273 w/ 727 auto trans. im going a '77 318 and same trans. im putting the TTI headers on it. i want to go to power steering, but i can't seems to find any posts that have to do with this problem direct. here are the questions i have....

1. will a power steering gear box fit with those headers from TTI?
2. if so, can i use a stock power steering box or do i need a smaller after market one? where can i get it, etc?
3. if you have this set up on your car, can you tell me anything to watch out for or anything i need to do to make it fit and work correcly?

Thanks FABO for your help!