Not offering advice, but instead, sharing an experience. I recently installed a Lunati Voodoo 262/268 in my '71 GTO with a stock 400 engine. This cam serves my purpose, but I really don't have anything to compare it to. The motor runs well and has adequate power, but I do think it is a little sluggish. Maybe not the cams fault. Good idle and response. About 17-18 inches of vacuum. This cam came highly recommended by a few who I admire and respect their advice. I have no regrets. The cam I removed was also a Lunati. High performance. Thought it was choking the engine. Best wishes with your selection.