Megan, I am assuming you are talking about outers, yes they are the same. They are also very easy to change, just pull a wheel, loosen the jam nut behind the tie rod end, pull the cotter pin, remove the castle nut, smack the threaded shaft loose and unthread the outer from the inner (this is the important part, COUNT THE TURNS AND PUT THE NEW ONE ON THE SAME AMOUNT OF TURNS, this will get you close enough that it should not drive real bad to the alignment shop, yes you will need an alignment). Repeat the same steps on the other side and you are done. I used to do front end work and alignments for a living and could knock these out in about 5 minutes per side on the alignment rack, in the driveway being your first time should take less than an hour.
Fine, I did the swap and on my II they are different the McQuay Norris part ES429R are for the manual rack ES455R are for the power rack. TRW and MOOG also use these numbers and have a $20 higher price for the PS version.
Jeff, I see what the issue is now. If you go back to parts america and put in 1976 instead of 1978 you will see only 1 for either power or manual but if you put in 1977 you will see a start up date of 6/27/77 for the different power end. I see in your signature your car is a 78, mine is a 76 so I was looking up my car. So it looks like we found yet another oddball thing on the late 77 - 78 cars.
There are two different tie outer tie rod ends for the II, a short and a long version. From 74 to mid 77, they used one for power and one for manual (I've never seen a factory manual rack II tho). Starting late 77, they went to one end for all applications.
I went through this myself, when I converted the Thundersnake over to a manual rack to clear the 5.4 oil pan.
About a year ago, I pulled my power rack off to replace with a manual one, not 100% sure if it was flaming river or not. I did buy the rag joint piece from flaming river to connect to my column. Anyway, I put both side by side to eyeball the width so I could put the manual in. At that time I noticed the tie rods looked shorter on the manual rack and I had to back out to make wide enough. My car is a 76 cobra II. This seems to go along with this threads discovery. My question is. When I go to have it aligned, will there be enough threads(space) if the alignment needs to go wider. I've always wondered about this. Not sure of the alignment process, except they must turn that rod in or out for the width. Does the shorter tie rods affect this?