I can buy a new pulley at sobering expense.
There's just too many variations to expect to find as a used or surplus part, exactly the one needed for a particular job, unless one is very lucky. ...especially in a small market like Australia. - diameter,, belt section, bore, number of grooves, material.
But I thought I'd give it a shot and ask here.
I have a box of various sized pulleys, and suppose others may do also, perhaps under a bench at the back of the shed.
The shaft on the alternator is 1 3/8", or 35mm - so close I think either would be OK.
Looks like Taper-loc (and similiar) are pretty well standard these days. These seem expensive too, even though they must be produced in huge numbers.
I can understand why they are popular. My alternator's old pulley (wrong diameter) was steel, 4 groove and with a long key - and very tight. It did not want to budge, until I brought in heavy weaponry - a custom puller made from inch thick steel plate, with an hydraulic pump and ram, and a blowtorch.
I'd be happy with a plain pulley, even if the shaft hole is too small as I can bore it out.
Come to think, if it's too big, I could bush it smaller.