1. Put aside $100,000 2. Contact Classic Team Lotus 3. Join the Historic Lotus Register... 4. Meet some owners and fly out to visit them with a camera, note book and lots of measuring tools. 5. Start acquiring parts: castings, engine, transmission, wheels - cause you can't find many parts for F1 cars at Pep Boys.
How about a Brabham/Repco? It would be a hit "down under," it has a tube chassis, it uses a production block, and it was the championship car. It should be easy to copy the tube frame because it was also an F2 chassis. This would be a less expensive home building proposition even if you are an airframe builder. You can buy a Cosworth for $150K US, but the rebuilds are about $50K for one vintage season. You could build and run a single cam V-8 for less than one Cosworth rebuild.
I shot about a hundred detail photos of 49R6 and 49R11 (49R2?) to aid in building the Tamiya Type 49 kit. Many of them used to be online, but I can't find where they are on the Web now. Obviously, I have them here.
I would also look at Michael Oliver's book on the Type 49.
I don't know if any plans are available for purchase. Contacting Classic Team Lotus would be the best place to start.
All I have ever seen is period reproductions of Team Lotus' GA drawings. I have one of the 2nd rev of the Type 72. Never seen anything more detailed than that.
There is a guy around here who was building a GT40 from scratch under some kit car bodywork. He used to build aircraft jigs at Boeing. It looked pretty good when I saw it a few years ago.