I have a 67 Sport Coupe Camaro with a big block. I only have about 1/2" clearance between valve cover and brake booster. Any suggestions on how to solve this problem?

Do you have the short valve covers? There is a short valve cover that is designed for this purpose, it has a small indentation on the rear of it for the booster. All big block Corvettes had these whether they had power brakes or not. One of these covers may solve your problem.

Make sure you have the BB frame mounts.