I realize there are a lot of vairables controlling the "backpressure" that you see (i.e. boost), often the cam overlap & minimal exhaust restrictions will lower this "backpressure". But you admitted the gauge showed 12 # - a difference of 3# from the MAP sensor. There are variables associated with hooking up the MAP sensor as well - have you verified the MAP sensors accuracy just for kicks? BTW, this is the "signature" of the person who's dyno results I linked to as a comparison... Seems like a pretty stout setup - that's why I thought it was reasonable as a comparison - I realize combo's can't be compared directly, but I just find it difficult to believe that you only have 9 # of backpressure (boost) with a 302 and those pullies - especially since you are seeing 12 psig pressure.