If your existing tqilshaft has replaceable uni's, you just need to change the front over to an L series one. The stanza box & the A series boxes are the same length. If the uni's are peened in, like on the Sunnys, a standard Stanza tailshaft from a H165 one 'should' do the job, as I've used a Stanza tailshaft with the front swap to an A series one in a Sunny with a H165. Hope you've got something like this hanging around.