Clear anodized or  you really mean natural.. ?
 The color I really think of a lot is the hard anodize color, which I think you can also get in paint to paint engine covers. 
 Will try to post examples. I think build-up is more  with hard anodize. 
 I have hard anodized a few things, very tough.
 For some reason I think a 750 motor would look a bit modernized,  with block, cylinder and head in silver,and engine covers painted as shown. Then maybe some billet to go with it with hard anodize of a close color.
Small parts anodized, covers painted maybe.