A518 in place of 727

A friend was showing me an article where a guy replaced his 727 with an A518. I told him I saw a string about that on forAbodiesonly. I have looked for that string, and cannot find it. I read it in "new posts", so I don't know what forum it came from. Could anyone give me some info on the tranny swap, or where that string is located? My friend has a '68 Barracuda Fastback 440/727 and a '69 Barracuda Notchback 318/904. He's planning on doing the work on the '69. If he likes it, he wants to do the '68, also.