89 242 with a 454 mag. Running a 21p 4 blade stainless spinning 4600rpm trimmed out with a couple people and half tank. Been meaning to send it to bblades to do a little labbing and get the rpm up a couple hundred. When running a 23p 3 blade I'm around 4900 but I like the 4 blade cruise and hole shot. Motor says run between 4600-5000. Being at that bottom number am I hurting the motor at all? Thanks for any input

No . . .

No you are not lugging if you are in the specified range although it would be faster and easier on the drive if you are closer to the top end of the range.

+1