Power Steering and GT-40 head questions

Any time you want to know if a part for one car will be the same as another, you can try Autozone or Advance Auto's websites and type in the different cars. If they come up with the same part number, you're good to go.
Not sure about the Gt 40 heads but you will gain very little from the swap. You may even lose compression costing you big power. Your heads have small chambers and the later heads may be larger , killing any flow advantage. The only way I would consider a head swap would be an aftermarket alumium head such as AFR.

i thought of same kind of swap with my 351, with 69 heads. They had a sale on GT-40Y aluminum pieces here, but decided to stick with the ones I have until I have money to get some AFR 165´s or 185´s ...

The difference really isn´t worth the swap, even on paper...

Of course if you wan´t an original replacement, it is a choice between having your old heads rebuild.