I currently have a 9in rear end out of a granada, not my choice discovered after I bought it, but I want a five lug rear wheel conversion for when I put the five lug disks on the front. I have found a 8in rear end for cheap anyone know if I can take the axles out of the housing and use them in the 9in I have not had time to take a serious look at either and have not had time to research.  

I didn't know a Granada ever had a 9" rear end.  If it is a 9", the axles probably won't fit.  

Well that maybe true I am not completly sure but I plan to put a 80's V8 and 5 speed in it someday do you think the 8in rear end will be able to handle the horse power and yes money is an issue so buying a new rearend is out of the question  

Hi bluemustang67 - Some, if not all of the Granadas had 9s.  I took one with the front disk breaks and spindles out of a 77 Granada 10 years ago and put them in my 68 FB. I'm not sure why you wouldn’t want to use the 9 you have? Is it a 4 for 5 bolt pattern? The 9 I had was a 5 bolt.  Mechanicalguy48, jlg2002, or others here will likely be able to tell you if you can use the 8s axels in the 9. I think that the widths are likely different and you probably won't be able to interchange them. Depending on you car year, you may only have to move the 9s mounts to fit it to your car. If not then you might have to have the 9 cut down 2 or so inches to fit. I could depend on the tire/wheel combo you plan to use. You'll have to measure the axel width and tire/wheel combo and see.

As for the 8, mechanicalguy48 (I believe) answered another persons question on this a few days ago - the 8 should handle up to about +-400 HP.

I hope this helps some. Again there are others here that know more than I do. I'm sure they will tell you what they know. Good luck!  

Well blue
My guess is you will not be able to interchange them. There are so many combinations, there are different spline counts, different bearing sizes, different taper, and not the least of which is different length. You might get lucky and have the same splines, but to have the length and bearing size the same I would think is remote.
The 8 inch is a stout rear end and you will find it in a lot of hot rods because its so cheap and you can change ratios so easily. I personally have had a 350 hp windsor with an 8 inch that lasted just fine. I have never seen anyone scatter an 8 inch, not to say its not possible, just that they are pretty durable. In car circles parts take on a kind of mythical legend where one guy says ,,,yeah those transmissions are just bulletproof and then everyone believes it. Its like that with the 9 inch. In all of hotrodding you will not find a more legendary part, outside of say the small block chevy. So people put 9 inch rear ends into their cars for the "cool" factor as much as for the actual strength. You said you want to put a 5 speed in there and the most popular and affordable 5 speed is the T5. Driveline parts like engine parts should be matched for strength. Taking out an 8 inch for a 9 inch thats in front of a T5 is like having a steel shank on your cocktail glass,,,,its gonna break anyway !!  That 8 inch rear end is plenty strong for a T5 and the 9 inch is overkill, but hey ,,,, do what makes ya feel good. Lots of guys do it for the "cool" factor and I dont blame them.