There are only 2 strokes: 228, 236, 248: 3.8125"; 256, 270, 302: 4.000". The 228 crank was probably lighter.
...Edit
Panic, yes, that's as I understand it, and I've read (here and in Clai Bil's book) that the 228 crank is lighter than the 248 crank, but I don't have 1 of each to weigh, so I have to go by what I read.
