I prefer O-ring fittings for the gear box
drain backs. These are sometimes hard to find.
Speedway Motors have them along with a zillion other
useful parts. A pipe tap will work but crude :)

They also have a 1/2 20 magnetic drain plug.

For the rear motor mount 1/2 inch titanium bolt saves
a few ounces.

speedwaymotors.com

The rubber rod end for the rear motor mount
strut you get from:

http://www.midwestcontrol.com/series.php?id=190

Paul Lamar