For bolts and machine screws, I used a mail-order Internet company here in the USA called Bolt Depot. Cost a bunch as there are so many large bolts in the T-16 but figured it was better to replace everything since it was a complete ground up restoration. I used stainless in most places. Link below is their company:
http://www.boltdepot.com/hex-bolts.aspx
For brass fittings needed with the two oil coolers and all the various lines, I used another Internet company linked below. Austin is a big city but a lot of this type of stuff just isn't readily available anywhere that you can walk into. So placing an on-line order was a lot easier overall, even though you need to think things out in advance for the project.
http://fittingsandadapters.com/