Finally gave Frank and Kurt over at Komet Motorsports in St. Charles a couple hours to mess around under the hood (check the timing, jetting, floats etc...) and
they found another 50hp. The RWHP is now 375. My Ford crate 392 is bone stock - no modifications - running through stock Backdraft side pipes. If your in the area and need a tune or Dyno- call 630 584-5400.
Obviously the car was out of tune when I got it, but this is clear evidence of what a good tune from some good mechanics can do. I still have not changed the heads to AFR and it does not have the new "Z" head that comes with the new Ford crate 392 (that engine is rated 475hp, mine is supposed to put out 430hp). Seems Ford is underrating these a bit because my flywheel HP must be between 450-465 to put 375 to the rear wheels (right?)
Unfortunately, I could not test the motor without the pipes because the headers did not exit the car and I did not want to melt the fiberglass as I did not have a collector that exited the side of the car. The mystery of HP loss on the BDR pipes lives on, but based on these HP numbers, I think Reg Dodd at the Backdraft dealer in Florida was right, 8-10 hp loss, not 40-60hp loss.