340 to 372 stroker kit
Although a little pricier than the scat, Molnar technologies is worth a look at on the stroker stuff, too. If putting a set W2 heads on a 4 inch stroke .060 over 340 at 423 cid, a set of aftermarket ductile iron caps with studs with a girdle would not be a bad idea. That would really depend on the severity of usage and how much strip time the car may see.