Tell me about the 413

The only reason I'd buy that would be to flip it to make some money. $150 is a good price if its in decent shape, not blown up or seized. If you're trying to build a powerful engine you'll do far better to start with a 440 or 400. I'm scratching my head seeing guys having so much trouble finding 440s, I've found and bought two 440s and two 400s dirt cheap. A cast crank 440 is the least expensive way to build a good low to medium budget engine with plenty of power and if your budget permits the 440 and 400 are both great for even more power with stroker kits.