which power steering box for 63 nova?

WE are looking to upgrade to power steering on my wife's 63 Nova SS. It is a floor shift automatic car, with a 194 six for now. I have read that CPP has 2 boxes available(at least the website says so) but does not have much info on which works for what reasons, the Delphi 600 and the 400 series. Can't sit on hold forever either.....

Anyone have experience with either box? We will be upgrading to a V8 in the near future but keeping the stock front sump style pan. We are keeping the stock front clip too.

Thanks in advance.

I too am trying to upgrade my steering on my 56 chevy, so far i have heard nothing but good from the people I have talked to so if you find out something i could use let me know.