I'm currently running a shooter 27 on my 1991 JohnsonFastrike 150hp and it has a small 3/8 wide band at the back of the prop that is about an 1/8 of and inch lower then the reast of the prop like a neck down .I picked a another 27 Shooter off my freind new in the box used twice and it doesn't have the neck down or area that I'm talking about what would the differnce be and will it make a differnce in performance???