I have a 79 Z28 subframe that I want to bolt up to a 71 Z28 are there any problems with doing that everything looks the same. Also I believe the doors to be the same if anyone knows any differently please let me know.

They are not the same. The 2nd gen subframe changed in 1975.

1970-74 subframes have a length of 28" from the rear subframe bolt hole to the center bolt location (which bolts just behind the firewall).

1975 - 1981 is 31".

Are the steering components the same including the power steering box.

Yes and no.

They will work BUT ONLY if you use EVERYTHING.

You can swap the whole steering system side to side, but they did alter the components slightly so it is best to take everything rather than peice it together. The upside is that the whole setup is beefier than the '71 stuff.

Honestly, I'd get all new stuff anyway, for the price it just isn't worth the risk of failure.

The lower bushings are different in the a-arms but this is only an issue if you're ordering it to fit that specific application...

The steering box has another issue, the input shaft is a different diameter from the '71. So you can either cobble together a rag joint to work (I believe Lee enterprises sells one to work with this setup, or any later box, or you can make one out of the two old ones.) If you are going to this trouble I'd recoomend nixing the '79 box (even though it is a better one than the '71's) and putting in an Iroc box