As for Dry Sump systems, there are not allowed in G1 period (66-69), that is for sure. I try to homologate my car in G2 period (70-71), only because the dry sump systems were allowed by the SCCA from 1971. As confirmed by your European racer, almost anything could be use under appendix K as long as you can prove it has been used in period. My guess is that from 1971, as dry sump were allowed, some teams moved to this. The problem is that the 1st gen Camaro was already an old car, and that probably the top teams which could afford dry sump already had a 2nd gen Camaro in 1971. On the other hand many 1st gen Camaro were raced in the 12 hours of Sebring and 24 hours of Daytona in 1971 and I think at least one of them should have used dry sump.
I have noticed the following teams in 1971 racing a 1st gen Camaro at Daytona or Sebring :
- Ray Rimble / Houghton Smith
- C.C Canada / Joe Hines / Wilabur Pickett
- Richard Small / Robert Fordyce
Would you have any pictures of these cars in 1971 ?