Griff: The 175 had a length of 17'5", a beam of 7'5" and weighed 1500 lbs.
I don't recall the year, but the 180 just stretched the length by 5" to 17'10", kept the beam at 7'5" and the basic layout remaind the same. The weight went up to 1800 lbs. on the 180.
Rob