BRISTOLRE
The -8 will still need to make a tech stop since it's maximum range (around 4400 nam) with a full payload is not sufficient to make it non-stop from anywere in Asia (with the exception of Japan in the wintertime) to the West Coast.
Volumetric capacity of the -8 is 30312 Cubic Feet what is roughly 4000 CF more that either classic or the -400BCF but I totally agree with INTRUDER; most the time you run out of payload ability rather that volume.
ACMI rates on the classic have dropped mainly because of the price of fuel. Cargo Airlines are no longer able to operate them at profit and unfortunately some ACMI carriers are willing to drop their rates to assure that the keep the business. Last year the going rate for a 747-200F was around $ 4,900.00 per block hour based on a 325 hour contract; These days they are offered at $ 4,300.00 or less. Half your revenue is allocated for MX so it become near impossible to make a penny.
Will be interesting to see what happens to the -400 rates when the 777F and the -8 become available.
LASPILOT