340 not running anymore...Help Please?

The car doesn't necessarily need to be running to get an index. You can crank it over and the fuel pump will either quit pushing fuel when the needle closes or it will flood over. This however is dangerous as any spilled gas will only need a spark to ignite. I would remove the bowls and visually check the needles and seats for any debris, a small speck will keep a needle from seating. While you have the float in hand put it in a tray with some fuel and see if they float or sink. They should float. After that reinstall the float and turn the bowl upside down to make it go against the needle seat and you'll be able to sight it close.

Dave

And what Dave (dgc) typed while I was typing...get a book..