aluminum driveshaft question

That is NOT right. The seals are the same, and the grease makes the joint last much longer. A dry joint grinds or seizes then fails. Unless you have the torque to twist shafts and splines, the greaseable one is often the premium part. Install the grease zerk on the compression side and crack failures will be minimalized. If you only go quarter miles or do not mind checking the joint regularly, then go solid. But not because solid is a better made part. It will not be.
 
I have the aerostar shaft. I haven't put it in yet but heard it is a good replacement. Is it comparable to the FRPP at all? I still need to buy the u joints and everything to make it work but it only cost me 13 dollars so why not haha
 
I have the aerostar shaft. I haven't put it in yet but heard it is a good replacement. Is it comparable to the FRPP at all? I still need to buy the u joints and everything to make it work but it only cost me 13 dollars so why not haha

You asked about the Aerostar drive shaft. Here are two places to look on the Tech board when thinking about something like that.

Technical Thread/How-To Index

http://www.stangnet.com/mustang-forums/threads/technical-thread-how-to-index.808661/

It also has a short belt thread and piston to valve clearance check thread that both came up again.

Official Thread of Applicable Junkyard parts for Foxes

http://www.stangnet.com/mustang-forums/threads/official-thread-of-applicable-junkyard-parts-for-foxes.564659/#post-5291433

I do remember reading it is larger in diameter than the Ford racing one. But I do not know that from experience. The price was right on yours, even with new u joints.