Boeing expects to achieve improvements in the payload-range performance of the 747-8 through weight-savings and engine enhancements.
Speaking at the Paris Air Show, Boeing Commercial Airplanes chief executive Scott Carson said the airframer "continues to look at product development studies that will allow us to further increase the payload and range of this airplane and to improve its noise footprint".
The first General Electric GEnx-2B powered 747-8 freighter has passed 50% completion at Boeing's Everett plant, with power-on expected in the third quarter and a first flight before year-end.
The first example of the 747-8I passenger variant is due to enter service in the second half of 2011.
Boeing quotes a nominal range for the 747-8F of 8,120km (4,390nm) and 14,800km for the passenger version.
"We'll continue to look at range and payload, particularly for cargo," says vice-president for airplane programmes Pat Shanahan. "Range and payload have not been an issue on the 747-8I."
Shanahan says that these gains will be achieved "through some of the engine improvement programmes that we'll have with General Electric". He adds: "We also have, like with the 787, the normal weight-reduction programme that you have with all development programmes."