Hello
Ups sorry, that link went to a Space shuttle astrounout ( sp ? ) witch starte his carieer as race mechanic from Donahue.
OK the 917 was very close to a street rocket.
AFIK Porsche wasn´t involved in rocket engeneering. If yes then Porsche would be today a american company
They did some research in developing those Jumo and BMW jet engines. Mostly how to realize the lighwight parts for high reving units.
Grüsse