In answer to Neal Garvin, in my case the answer is simple. The airplane was
designed that way - and judging from the number of experimental accidents
attributed to fuel system design, I wasn't willing to throw those particular
dice. Add to that the fact that my LNC2 was an early unit (even Lance's
prototype 235 wasn't flying when I bought mine - the 200 had flown, but I
don't count that) there were a number of other more pressing issues to deal
with.

Plus the fact that with a full header tank (I always keep mine full, or
nearly so) with a complete failure of every pump, including the mechanical
pump, my engine will keep running at reduced power on the header-to-carb
head pressure for quite a while.

Dan Schaefer