Is there an online source to check out V numbers for 757 and 767.
The main design speeds can be found on the Type Certificate Data Sheet, which is a publicly available document.
Go to
http://www.faa.gov/, select the 'Licences and Certificates' tab, then under 'Aircraft' there is "Type Certificate Data Sheets (TCDS)" which links you to
here
You can then look up a specific TCDS by make/model etc.
For example,
this is the B767-200 TCDS.
Airspeed Limits: VD = 420 KCAS to 17,854 ft/.91M above 23,000 ft, linear variation between these points.
VFC = 390 KCAS to 17,600 ft/382 KCAS at 23,000 ft/.87M above 26,000 ft, linear variation between these points.
VMO = 360 KCAS/.86M
VLE = 270 KCAS/.82M
VLO = 270 KCAS/.82M