Well done! I had a 2000 Chevy company truck with the same drivetrain. Loved every minute of it! Nice Swap!
My 1969 327 smallblock with a Rochester 2BBL/ Hedman Headers, Granny 4 speed 4.11 rear in a 1970 C10 Shorty, would provide 15 MPG. That was turning 12 by 15 inch Jackman wheels with a 12 inch Winston offroad tire.
Demonstrating the efficiency that even stock modern Multi Port fuel injection, Ignition systems and especially newer electronic OD transmissions provide over earlier non OD transmissions, TBI EFI, Carbs and earlier stock ignitions. Cheers!