I have a 1989 celebrity 181 bowrider, but mine has the 4.3 with a 19 pitch prop i can hit right about 50 on some smooth water when i find the sweet spot on the trim. i'm gonna guess the 3.0 should maybe touch 40.
I used to own a 181. Bought it new and sold t to my brother 10 years ago. He still has it. Fantastic boat. Extremely solid hull. 23 years old and there is not one stress crack anywhere. It has the 4.3 which has loads of power. My only complaint is with the modified v hull it does not take rough water very well. A perfect Table Rock Lake boat where there is miles and miles of glass smooth water. Wide open trimmed out just shhy of 50 mph.