once the leak issue was figured out i have had no problems with mine. when the car had the four spd and a four barl carb 12 mpg was the best it would do. switched to a six pk and the keisler now it gets 20 to 22mpg.. i found that when modifying or restoring these old cars there is always some issue that you have to deal with, good responce from manufactures helps in dealing with these issues.