cam shaft selection

got a 73 valiant with 318 was hard to start then started missing turned out i lost a cam lobe. i want to replace the cam with something that will lope but still work with my stock 2bl carb until i can get a 4bbl setup. summit has a cam with a duration of 262/272 and lift of 420/442 i think the centerline was 110. ive been told by different people this will change my idle and some say it wont. any help would be greatly appreciated hoping to order something this week. i drive a truck and have till friday to get the order in. thanks