Old hull was pre 1986. The old hull was a true dory hull, flat bottom, hard chine with two skegs. The new hull is a rounded chine, sharper cut in the bow so she will not pound and will cut the water better. The new hull also has a wider beam on the transom so it could hold four stroke engines which are heaver.
I have a 1983, and when I added a four stroke engine, I had to raise the waterline about 3 inches. though she pounds at higher speed, she is very seaworthy.
Which is better. I love my boat, so the choice is yours.
Fred