i think diff housing and gearbox date castings will be the next big thing for "matching numbers"
Paul HQ SS has done alot of good work on this and has a database of aussie 4 sp,

he would appreciate serial numbers off them if you can supply...

lets face it, most sandmans are L32 M20 so it will come in handy.....

paul... HQSS@oldholden.com