That forged crank is old technology with respect to metallurgy. I believe that they are heavier that modern forged. Poly heads can produce 400-500 HP max. Now you can throw nos,tc and sc at it, but not worth it. Custom pistons and intake $3000.00+. Funky yes. Neat yes. Results mediocre from what I think you want. A 331 hemi will make more power and all the parts are available. Then there's the 354 and 392 also. There is a poly website. Check it out.