Classic/Antique Car Repair: 72 chevy c10 p/u - hard to keep running at first, 72 chevy c10, k n air filter

Question
I have a 1972 c10 pick up with an original 350.  I can get the truck started fairly easily but it stalls unless I rev the engine for a few minutes then it runs perfect.  I put a K&N air filter in place of the original air filter. Did I disrupt something when removing some of the original hoses from the air filter?  I know this seems real basic but I am new to restoration and trying learn best I can.  So far so good on other problems!  Thanks.

Answer
CRAIG ;
 Hi ; I wonder if you might have left off a small vacume line that goes into the air filter , that would cause it to stall . Listen for a sucking sound , when looking for it, your filter might not have had one but that is the only thing I can think happend to it. if the air filter is the same size and it fits into the same holder than it should be fine, did you try to turn the idle up a bit. but look for the hose first .  ok