Phil,
Basically the specs for the 184 Ghost are identical to the 183 Ghost but the hull has had a design change to accomodate a 175HP engine. The 183 Ghost had a max 150HP rating with the demand from more tour anglers and customers for more speed Ranger Boats filled the gap with the new 184 Ghost.
I personally ran the Ranger 184 with a Evinrude E-tec 150 HO and it acheived a speed of 53 to 54 mph at 5500 rpm's, plenty fast for me. With a 175HP engine you can expect even greater performance out of the new 184 Ghost!
"Don't be a Googan!"