I owned a 1976 Hunter 27 from 1980 to 1983. My boat significant weather helm, and the tiller was cracked from the strain. I suspected a bent rudder, it hand down BELOW the shoal keel so running aground the rudder hits. I got dimensions from Hunter and measured my rudder. It was bent back about 4". I measured about 6 other 27s in the marina. Most were bent worse than mine, one was bent 11"! I straightened it my self in a hydraulic press by hanging it from nylon slings. I then inserted another pipe inside the tube to stiffen it. After straightening the boat could be trimmed to sail for 1/2 hour at a time without touching the tiller. I've sailed boats with wheels, I'll take a tiller any day. Better feel, more room in the cockpit when docked or at anchor, less to go wrong.
At some point, 1977, or 1978 I believe, Hunter changed the keel to hull connection because the bottom of the hull would delaminate, like mine did! The keel very nearly fell off. When I fixed it, the boat sailed so much better you wouldn't believe, and never had water in the bilge again. It's easy to tell if the Hunter you are considering has this flaw. Pull up the floor boards. If the bilge is shallow, about 3", and has a raised flat bump in the shape of the keel, where the keel is inserted into the hull, pass on the boat. If the bilge is about 8" deep it is the fixed design, and should be okay.
I had a jib sheet get caught in the prop and it very nearly ripped the strut out of the hull. Realizing that this would have sunk us in minutes, I greatly reinforced the area around the strut and also the rudder tube at the same time.
I liked my Hunter 27, believe it or not, and did extensive modifications to it, both inside and out. The guy I sold it to sailed it offshore for the next 10 years with no problems.