This is the new and the original alternator. 

This is the rear view and as you can see, the three (3) wire connector will be the same.

The connector plug fits in exactly like the original Lucas unit.

The mounting position and adjustment are the same.

This little retainer is a great idea and it does fit perefectly over my stock plastic connector.  This alternator
apparently fits a few models, because I don't think that this was a Triumph clip, even on a Spitfire.

The pulley that comes with this look a bit too small, so I measured both for comparison.

This part is close enough.

Even this isn't too awful bad....

When compared to this.

This is a bad picture by yours truly.  The width at this point is .380" or 3/8".

It doesn't take a rocket scientist to see that the original 1/2" wide belt is going to have a problem fitting in the groove above.

Just a side view while some answers come in.

GregL from the 6-Pack Forum saves the day with this fan/pulley kit from Mr. Gasket (Summit Racing is where I got mine)

This shows what comes in the kit.

Now we're back to 1/2" width for the proper belt.

The new pulley is slightly bigger in diameter, but remember that we were only off by .400".

This shows the difference in the width a bit more clearly.

And the diameter is nearly the same.  By the way, the pulley goes on with this side facing against the fan.

The new fan and pulley are on, but the chrome is covered so I can apply a few coats of high heat clear to keep it nice and clean.

There it is.  Already to go, along with my new polished stainless adjustment bracket.  More bling to add up front.

The bolt used here is an 8mm 1.25.  It is NOT 5/16" coarse thread as I had thought.  I did get a different
bolt for this, which is a Flanged bolt.  It has a wider bottom to the bolt head and won't gouge up the new bracket.

This is sitting on the bench for the next few days waiting for the clear paint to harden before I install it.

I had a few minutes after lunch today, so on it went.

The little clip over on the back snaps in place nicely to secure the harness connector in place.

The black rubber boot came with it and I added the white to protect what is probably a "hot" terminal.

This is the flanged bolt that I used in place of a bolt and washer.  Old GM ways are still in me I suppose.

I added a nyloc nut & lock washer to the back, even though the alternator housing is threaded.  Just like wearing a belt and suspenders.

This is a new nyloc nut and lock washer as well.

All done and it looks at home.  The chrome pulley and fan go together with the polished stainless bracket,
which is much heavier and stronger than the factory bracket.  That's not a bad thing, but it is one more thing to polish.

This will definitely make a difference with the TRF Halogen PL700 headlamps and the new seat heaters.