La fan blade bolt threads fine???

The bolts i pulled off the pump originally were coarse thread. I don't know why or how. I wasn't sure if the old pump or the new one(painted to match the motor) was correct. The motor is a 360 and obviously isn't original to my 64. I believe the block date was 1979. As I stated before the bolts needed are ordered and yes they are 5/16×2 3/4 fine thread. Thanks