if it is a rochester B I would bet money the power piston is sticking, I finally polished mine w/fine steel wool to get it to work properly-I got 18.5 mpg keeping it @60 or below. started @12.5 mpg. carb are simple & a repair kit here runs about $13. An HEI will also help emissions/MPG. I still can't believe they smog a '58, I mean it came with NO emission controls, they weren't even avaliable. brian
