Ali...I presume he means the early engine shown in the top photo as opposed to the bottom AJS Stormer photo. What
exactly are you looking for? I presumed your Sprite already had a Villiers engine
. If you're intent on a Starmaker engine, you may be more successful directing your ads on the Swapmeet towards asking for an AJS Stormer engine as many folks might not understand that the engine is actually a Villiers Starmaker and think it's an AJS 2 stroke. Why the need for a Villiers anyway when so many different motors were originally used. You may have better luck chasing down a Maico square barrel 350/360/400 engine to build a 'works replica'.
You could try a Kawasaki 250 or even an OSSA Pioneer engine, the one that fits in crooked
. Even more exciting, what about a ridgy didge Sprite 250? AJ might just be able to sell you one.