the 02 ls-6 cam inmy 5.3L does the same it peaks boost @ 3800-4500 rpm then the boost falls off, I've got the boost curve from the dyno tuning somewhere around here, if I find it i'll post it. I'm not sold on the "bleeding off boost" though I think its a factor of a high rpm cam increasing the pumping efficiency of the engine. holding the pulley size constant, the engine will move more air thus decreasing boost. although the HP will probably be better due to less temp increase from boost pressure. Or you can decrease the pulley sizeto up the boost.

 

Yes, I didn't mean to imply bleeding off boost. I think that is an incorrect phrase. I used it as an example to what we saw on the gauge. I believe it is more like what Flem stated about pumping efficiencies of the cam at higher rpms. The cam has a very tight 117.5lsa. I don't believe much if any boost can leak past that. It seems to be a very effiecient cam if it can do that to boost without bleeding it off