Two words .. Unsprung Weight ;)
On a light car, I like to have everything that is unsprung weight, as light as possible. I even have a aluminum 9 inch center section ( with a aluminum Daytona pinion support ) and a aluminum driveshft. :D The aluminum center section saves 22 pounds over a iron one. The aluminum driveshaft saved 10 pounds.
http://hotrodders.com/journal_photos...1772828870.jpg
The photo shows a BLACK painted driveshaft ... but it has since been replaced with a aluminum one ... :)
I also like to use aluminum parts wherever possible. I have aluminum heads, aluminum water pump and aluminum intake on the SBC.
http://hotrodders.com/journal_photos...1630215272.jpg
A small starter ... saves over 10 pounds ... ( but it is sprung weight ... like the engine stuff :whacked: ).
http://images.channeladvisor.com/Sel...D0190_SIDE.jpg