Flex Shaft- K&B 3.5 Outboard

I'm sure it might've been a mistake but a while ago I ordered 3 after my stock drive split (It was old so due to go) any fast forward a bit to long after they arrived I got round to replacing the drive and after assembling the hull the drive caused horrific resistance on the on the engine, it seemed to fit fine but upon inspections after attempting to fire engine (Hoping the shaft just needed to break in) I eventually decided to pull out and measure the shaft, it was too long (Not by much but enough to cause issues, exact numbers I don't remember I will remeasure) and if I remember correctly it was ever so slightly too large in diameter. I managed to find a stock flex drive by K&B in a spare bits job lot and it worked fine. I also found these shafts are actually very stiff to flex as well causing it to push heavily on the stuffing tube again causing resistance. I by no means intend any disrespect to the works you guys pull off as you are the only place I've seen new drives for sale for the 3.5 OB.