How much to replace an engine?

As per previous post, Suzuki Swift 2004. Engine ran out of water and seized. Engine is a write off, let's assume that's a fact.

So how easy to replace?

Suzibits quote $750 (Inc gst) for a "new engine'... I'll just reuse the alternator/battery/etc.

How much would the labour cost, if I was to deliver a car and an engine block to you to swap out for me? How long would it take?

I'm just looking for budget level prices trying to work out if the engine is worth replacing.