Hi,
Why don't you try an electronic ignition? I have a Pertronix's set up on my 292 and it pops off on the first turn of the swith.
I have 3x2 holly/webers. Be sure your fuel pump is pumping at it's optimal performance too.
Buy the way, what is your definition of "starting at the turn of a switch?"
RapRap
1940 ChoppedChevyCoupe