i am scratch building a new gen IV block with a Callies 4 inch stroke crank, a set of ls2 type SLP pistons,6.125 H rods,and a set of cnc ported cathederal port heads with 2.02/ 1.60 big valves ,at least for this type of heads.the cam i will be useing specs at 566/566 lift and 223 @50 for duration. will be useing a factory truck manifold,shorty smog leagle headers cat back exhaust work and a MAC air intake system. my questions are many. most important is what i have to do to my ECU. i see that the 5.3 AND THE 6.0 use a common ecu for either engine but seeing i'm upping the displacement pretty substancially will the ECU run this engine with out substancial modifacations. number two is do you think i can get threw California emmisions with that cam. number three do you think it is realistic to expect about 450 engine hp from this combo. any suggestions would be greatly appreciated. truck to be used for hauling 7500 gvw loads and for fun with the local ford SVT's and V-10 dodges.