Probably not. The '77 used ComStar wheels, and the rotor offset was different, making the caliper offset different too (or vise-versa). I tried using front calipers from a '77 on my '76 750F, and there was no way, unless I swapped out the wire spoked wheels with the comstars and the forks as well. So I'm thinking there are similar problems with the rear wheel as well.