You can purchase used engines for your Daihatsu Feroza / Daihatsu Rocky / Daihatsu Sportrak online from Japan.  For a list of vendors click here.  Original engines will have an 'HD' on the engine block just behind and below the exhaust manifold.  Another common engine used is the Daihatsu Applause, which is almost identical.  The only difference between the two is the size of the cam (but not much) so the applause has a bit more upper rpm range grunt.

Stock Feroza Engine Output = 70kw
Stock Applause Engine Output = 78kw
Stock Charade DeTomaso Engine (HD-E) Output = 92kw

The cheapest and easiest option is the Applause engine.  The Detomaso is the most powerful version with a different cam and EFI computer controlled timing- meaning you'd have to get one with the loom and computer to do the install.

'HD' mark on the engine block found below exhaust manifold.

BUYING TIPS: When buying a used engine, ask the seller approximately how many miles are on it and what the warranty is.  Typically they will claim 50,000-60,000 mi and warranty the engine for an average of 90 days.  They will also recommend that you replace the front seal, rear seal, water pump and timing belt when you get it.  The only thing they do when they get the engine is a compression test and a leak down test.

Are used engines from Japan still good?  Why did they get rid of them?

These facts are not verified, so keep that in mind:

1. New cars in Japan are cheap.
2. Yearly emission tests in Japan are very strict.
3. The repairs to pass Japanese emissions when the engine has ~approx 50,000 mi. on it apparently cost more than a new car.  So they get a new car and discard the old one.
4. Japanese mechanics are not allowed to re-use old parts for repairs, they can only use new.  This creates a surplus of used parts.
5. Distributors in the import/export business figured out they could sell used engines to countries with comparatively laxed emission policies who re-use old parts.

EMISSIONS NOTE: For those living in the United States where emissions testing is required you will need an Exhaust Gas Recirculation (EGR) valve.  Make sure that the engine you are purchasing either (1) has an EGR valve or (2) your existing engine has an EGR valve.  The EGR valve is part of the intake manifold so in the event the engine you bought doesn't have one, just swap the intake manifold with the one you already have.  The bolt patterns are identical.

On the left is an intake manifold with an EGR valve (blue arrows); to the right is an intake manifold without an EGR valve.  The one to the left also has the fuel injectors still on it.

While swapping intake manifolds it is recommended that you take the opportunity to clean out the EGR valve.

What is a Compression Test?

A compression test is done by screwing a gauge (compression tester) into where the spark plug goes to read how much compression builds up in each cylinder.  Low compression will mean a leak.

Is a Compression Test accurate?

The problem with this test is that there are too many variables. It can only be used to check engine condition by comparing cylinders to each other or a past norm. Variables such as cam profile, engine cranking speed etc, will affect the readings.

What is a Leak Down Test?

A leak down tester uses air from a compressor and measures the rate at which it leaks through the engine. This is done with the engine not running and the beauty of this is that toy can find the source of the leakage by listening for the escaped air. Internal leakage is found by air bubbles in the cooling system. Tools need are a leakdown tester, and an air compressor.