oil pump rods

my suspecion is that there are two different lengths due to different oil pumps. I will check my book and confirm there are different part numbers. From personal experiance, I used a stock shaft to drive an FE high pressure pump(Melling 55HP) but needed an extra bit to use an FE high volume-high presure pump. I would first look closely at the oil pump and determine what it is then determine which oil pump shaft is correct. You might want to invest 30 dollars in a heavy duty shaft while you have it apart. TJR