What i did when we built my engine was get a list of say a 1916 cb performance engine kit so i knew exactly what i needed, i then sourced all the parts myself from vw parts unlimited or cip1, i ordered it in separate orders so it came in under $1000 per order so i didn't have to pay any import taxes.... Although i'd give Rod penrose a call before you do anything as his prices seem very competitive with buying from the states at the moment. Have a look at his online store
www.rodpenroseracing.com.au. i believe he is in the usa at the moment though so call him in a couple of weeks when he gets back. He should be able to put something together for you...
Mick