Search the forum, there is plenty out there on this. Talk to ogiehooker, he is putting together a motor at the moment. If you look up his thread, most of your questions will be answered.
The HRC stuff is very hard to find and is expensive. If it pops up, there are a few guys who usually grab it immediately and pay a lot of money for it.....ask me how i know.
HRC had a lightened crank, one actually popped up last year on ebay.
Horde performance will put a motor together for you or if you really want to talk to someone who knows what he is talking about, contact Roger Ditchfield at RevolutionUK. Very close ties with the Moriwaki family, and built a few VTRs for BSB. They still build Stage 1, 2, and 3 motors for the RC.
Stage 2 cams are available but require a stage 2 valvetrain.....which would be HRC or Moriwaki. Both are hard to find. Roger can help you out with that though. Kibblewhite will make titanium retainers with a special order.
Carrillo rods are available but ogiehooker was having an issue with them.
JE pistons are available and i believe are HRC spec.
I have all the HRC manuals etc on digits, i can email you if you want. Other then that your best bet is to search through the forum and speedzilla archives for info, especially for the HRC stuff.
If you go to my build thread, it will explain alot as well.
Last piece of advice i have is be careful of HRC parts. they are almost always used and all of this stuff was designed to be used in conjunction with other HRC parts. To get one part to work usually requires solving a puzzle and tracking down unobtainium parts which end up costing thousands of dollars for a few horsepower and a lot of work figuring how to get it all to work....because very few people owned or raced the complete racers. Its all a big puzzle.