The 340 plods along at around 0.82, whilst the -400 is more in the region of 0.84 or 0.85 (depend on the airlines op. proc. of course) So yes, at the same level the the -400 will close. The 340 will usually step higher earlier though (at heavy weights) so not always a prob. As you say human nature, like being in the circuit in a C210, and bitching about the Tomohawk in front.
Lucifer, what routes place a restriction on min. speed? I am aware of Mach no. technique etc, but have not heard of a route not being available to an a/c type per se. In my experience, he who is in front generally get to set the pace.
[This message has been edited by jtr (edited 19 October 2000).]