Oil or lack thereof

Have a 69 Swinger 340 that has very little if any oil getting to the left rockers. Right side is getting plenty. It's not the shaft,it's on correctly, notch forward and down. The rocker shaft pedestal, (2nd back from front) that feeds oil to the shaft appears to be clean. Question, should I be able to feed a wire down this oil feed? Seems I can only feed a wire down about 3/4". I read a post somewhere that a guy said you should be able to feed a wire all the way down to the cam. Hoping for any answer besides a cam bearing installed wrong. Engine was rebuilt by someone else several years ago and hasn't been started until now.