More specifically, where can I find the mounting bolts for the voltage regulator and starter solenoid, to mount them back to the inside apron? Wasn't sure if I could run to a parts or hardware store to get them. If so, what thread type and size must I look for?

 

You never mentioned what year of car. You could probably get away with just using some sheet metal screws depending on the size of hole you have in your engine compartment right now. Either way, you can get that kind of hardware at just about any automotive store, or a hardware store like Home Depot.

 

http://www.mustang-unl.com/emustang....SRCCODE=MUEWEB

 

If you are looking for the correct bolts and I actually bought kits from these guys as well. You can't go wrong. Not cheap,but worth it:

http://www.amkproducts.com/Ford_Master_Kits.asp

 

NPD and Cal mustang have bolts as well.

 

If your looking for the "correct" fasteners, then AMK is your only choice. If your just looking to get 'em fastened, then go the route of the local AP store or HD.