Regarding the posts on how "replica" does a replica need to be, I agree that it just depends on the pocket-book. For me, the mono chassis and a modern air-cooled Porsche engine is about right.
For somenoe to go truly original in a replica would be on the extreme end. The original car really got close to the ideal race car, which falls apart the second it crosses the finish line. The chassis cracked sometimes. They used to pressurize it and put a schraeder valve on one of the rear chassis elements. They would periodically check the air pressure in the chassis - if it dropped, they knew they had a crack somewhere! The bodywork was so thin that if the car was raced over 12 hours on a track that had some grit or sand on it the wear was enough that it would eventually wear holes in the front. The average thickness of the fiberglass body was 1.2mm, or 50 thousandths of an inch. They even diluted the paint with paint thinner so it would add less weight. The bolts on the suspension were titanium and they drilled the centers out to reduce weight. Even the requisite ignition key was drilled out!
Back to my question, though, anyone heard of horizontal fans for 6-cylinder Porsche engines? Or anyone have suggestions as who to call about such things?