Poly's are an interest of mine. Simply because nobody runs one.
I've heard some guys are pulling 400/500/600 horse out of them. I've been thinking it would be really cool to do a more door fury build. Suicide the doors. Blown 318 poly. Would be different. And different is cool in my book.
I haven't heard of anybody getting more than low 500's. The only limitation is the heads abilty to flow air. There is a fella on FBBO that is doing some wild work to the poly head. Very expensive work. But the flow rate was well increased.
The Poly will take any stroker crank the LA or Magnum can. Pistons are custom made for the kits or by yourself. Expensive yes. But then again, if it is to much for your wallet, don't cry about it.
Everything is expensive. Nothing new there so let's just move along, move along..... LOL!