DYNO disaster ? Help

That is actually a really nice Dyno Sheet.

It made 299/ ft lbs from 3800 - 4300
and Peak Hp at 5100.

Nice AFR's....a tad lean from 5300-5500., but its tolerable since peak power already happened.

It appears low on flow somewhere for the price you paid....but it is what it is.
9:1 CR and .480" lift cam wont be a monster....but you honestly should have gotten another 50-75 whp for the $$$$....I attribute it to the Performer RPM, and the MP Orange Box....I personally have never had ANY luck with a Orange Box.

Ohh and I am gonna say it!! Just because the mufflers say FLOW - master, the only thing flowmaster ever mastered was getting the money to flow out of customer pockets.....they are a restrictive muffler....designed to make a "sound", not FLOW.

If power is a concern, but you must be muffled, you want a straight through Glass Pack style muffler.