That may be a problem with this cam. I just got off the phone with Comp Cams asking for the spring spec for this cam. Lift will be .540/.549 @1.5 ratio and .576/.586 with 1.6 rockers. I told him up to 6500-7000rpm max, thinking of the future. He said it needed 150-160 lbs on the seat and 380-400 open. The problem is the relatively short install height on the stock length valve of 1.650-1.700" in the J-head and he said they didn't have a spring that would work.
@Rat Bastid any suggestion? I looked in the PAC catalog but the way the data is laid out makes it difficult to go through for me and nothing jumped out.