Long story short..I recently took off an 850dp and put on a 1050(#8082) on my 557 bbc. Runs ok If I "sneek" into the throttle/secondaries. If I stab it ,it all but dies. I thought I's start by playing with some different pump cams. I a little search on jegs and it says I can use part #'s 20 80 and 20 81. Sooo I go out to my carb and there is a pump cam # 643...wtf?? I dug out the pamphlet/owners manual deal that came with the carb and it also says 20-81 or 20-80. Now I don't have a clue what to buy....the 600 # asst. pack. or 20-80 and 20-81. Any help would be appreciated .