hey
i have a holley 3310-4 carb 750cfm
it is a 4 barrel an when i open it up with the engine off, only the front two open
is this making my engine suffer?
also it seems my car is only getting 3 miles per gallon

Hey! The rear barrels of a 3310 are operated by engine vacuum. They won't open with the engine off. If the car doesn't bog when you mash the gas, then they probably are working just fine. Your mileage will depend on many things, like driving habits, engine size and condition, car weight, and rear axle ratio to name a few.

ok thanks for the info
ummm i still think my sending unit in the tank is short cause noww i cant start the car again and when i lay underneath the gas tank and shake it i hear gas moving around
last saturday i dropped the tank and took out the sending unit, couldnt really tell if it was too short, put it all back together, put 5 gallons of gas in it and a little in the carb and it ran fine. i cant go far since the car is not on the road yet so i take it for small 5 min trips on backroads in my town and i cant really open it up i never make it to 3rd gear since every block has a stop sign. so that was 5 gallons added saturday and a five min ride, five min ride on sunday and monday now it wont start unless i add more gas
i have 4:10 gears
any advice will be deeply apreciated