It doesn't only look like a Spartan, it is a Spartan and the advert states this.
As for Jaguar engines being plentiful, have you tried to buy one which works?! True there were a lot of take outs, but 99% of them have something wrong with them. I have had 10 J60 engines, only 1 of them had nothing wrong with it. The rest have ranged from missing components, broken mountings & head gasket failures to holes in pistons and total seizures.
Chris