go to
www.ls1tech.com all those questions and a million more has been answered and you can search to see the dynoresults of every imaginable combo... but for anything beliw 500 rwhp (600 crank Hp) an afr 225 will be to big for a streetcar on a stock displacement ls engine..... a pair of hand finished afr 205 with a ported FAST 92mm intake, and a well engineered cam will put down 500 rwhp with a 6 speed and have gobs more torque than a simmilar 225 headad engine will... the problem is that the intakes for la engined really dont flow mor ethan 275 cfm... so if you want to actually ust those big heads you need more displacement and a singleplane intake like a super victor ....
but ls1tech.com is your friend