I always thought that there must have ben a reason why BA would not do LAX in the 741 , presumeably a bit more cautious than PA TW and of course they knew they had the much improved 200 series coming along , which iirc the Americans never ordered .
I also recall that the PA ones used to sue some odd non standard departures instead of the usual SIDs (Daventry I think in those days) .
Also was there the same east/westbound flight time discrepancy on LHR LAX as on LHR JFK or does the semi polar routing avoid the Atlantic winds-I should know I ve done the trip often enough but not lately.
PB