if you're just talking about an overbore, not really. the best thing you can do for the old hondas is deck the head and boost compression. There are usually big bore cylinders you can slap on but i'm not sure about all the different years and permutations. I know the real early ones are a little odd.
DrAtv.com/ beatrice cycle is my go-to for all that c70 stuff. they have a lot of good info but its hard to find.