i can say one big thing about that 05 up exhaust, don't touch it in front of that 2 into one. you lose power, have so much noise inside that you need to drive with all the windows open and loose mpg 's big time.

been there did that and it cost me over 3k to return it to stock so i could drive again with thw windows shut and a/c on.
infact i still have a pair of cut off cats sitting here from trying true duals on the 05 up v10. call me dumb big time . fred said don't he was 100% correct.

now as to flutter that reduced area of the y pipe was fords fix for getting rid of the flutter on the 2 valve motor and it worked as every guy in here who has removed the reduced area now has the flutter noise.

sorry guys but my bank account would buy my super charger kit for my mustang 5 times over for what i wasted on my v10 trying to get more useable hp and better mpg's. and we have only a small handfull for luckie guys who did get the super chargers on theirs before both companies making them and stopped production of them for ever.

the v10 is not a hot rodding motor! it's a gas work horse motor and thats it. if one thinks it can be raced forget it and drive it the way ford made it.
go buy a cheap used mustang and rod that up. stick the stangon a trailer and tow it with the v10 powered truck and have more fun then ever.

no punn intended guys just been there and done that, 25k of wasted cash on trying to rod a v10 05 sd sc srw 250. even changeing the torque convertor is a no go.higher stall it looses power so bad i pulled the traqns 3 times in 1 month and woun up back to a stock convertor