carb float levels?

i am rebuilding my carb. the instructions. say 3/8" from bowl to top of float. the exg. set up is closer to 3/4". I adjusted it as the instructions said, and now it backfires.. Is this due to the float being to high? What will happen if i lower the float? what problems will i run in to?

by the way it is a single barrel carter on a mopar inline six

 

If it backfires out the carb it is too lean. Raise the float level.
If it is backfiring a lot when you let off on the gas, the float level may need to be lowered. If it is backfiring out the exhaust under power, you probably have a mixture that is lean enough to not fire in the cylinders all the time... probably lean. It is really hard to diagnose without hearing it!
I was told by an old time mechanic to just set the float so the top is parallel to the top of the carb. It does usually work OK like that.
Just my 2 cents.

 

What kind of carb?

Are you holding the carb top upside down so the float is holding the needle closed when you measure for float height?

 

Old timer was right. Just follow the old gas stain line on the float body and level it the the carb body line. Like C9 says, upside down she goes, old man the float level, and then touch the tang on the top of the needle. If you have to bend the tang, bend the tang (only) and do not distort the fl oat's pin pivot arm. Bend the pivot arm and one side of the float will rise faster than if level. This shuts off the bowl level and there is your fuel quantity not keeping up with the vacuum draw from the cylinders out of the single carb fuel level.