'74 advance vs '76

The advance on the '76 engine will not advance through the full range. If I set it at F at 1000 rpms it never advances to full advance (everything is free, cleaned and lubed). If I set it to full advance at 2300rpms it never falls back to F except under very low rpms. So I thought about the '74 advance I have. Markings are different, but will it work and will the settings matchup? At first glance I think no, but thought I'd see if anyone else had done this.

Thanks

Is there any real difference between the two advancers? Don't make me go out to the bike and try it.:whistle:

Surely someone has done this.

thanks.