I have had a Morgan 35 for over 6 years and love the boat.
Theoritical Max Boat Speed = 1.34 x the square root of the waterline length (27.6 feet) = 7.04 knots
Design Heeling Angle: Lean as far as you feel comfortable. A little heel is good, an excessive heel is uncomfortable and will start to slow you down. I max out whne I can look over the windward side and can see the centerboard under the boat. Your call. I sail in Southern California and when going to Catalina in the afternoon, the wind is typically 15-20 knots and I sail a close reach with a reefed main and a 135 Genny with the centerboard down and make 6-6.5 knots without too much bashing. Sailing home with the same breeze is a beam reach with a full main and the centerboard up and average over 7 knots and hit over 8 knots with a little surfing. Boat handles it very well.
I get a kick at taking out people new to sailing and watching their reactions to the boat heeling over. "Is is supposed to lean this much?" I assure them the boat will not tip over. I have a tall rig with a 13'-6" boom. Most 35''s have a 15-foot boom. I know the boat well so if you have any questions, please ask.
BTW You can get most of your boat data at Sailboatdata.com is the worlds largest sailboat database.