Whats this chassis off?

[Mr Cool]

A friend of mine has this chassis that we cant identify.
There is a discussion on it over at ozrodders if that helps anyone.
http://www.ozrodders.com/board/viewtopic.php?t=6115
Now Holden built bodies over here in Australia for many makes of vehicles, from several different countries, and fitted them to imported chassis.

If anyone can put some light on this it would be appreciated.

[enjenjo]

Well, I'm pretty certain it is not a Chevy. The front frame horns are way too short, and Chevy used a bigger rear crossmember. But it does look like a GM product.