Guess!

RAMM said
That should make around 390-400 HP and 415-420 tq . Those heads aren't that good OOTB. J.Rob

I'm going half way with RAMM on this one.

I'd bet close to 400 HP but the torque will be 375-380ish.

I've done a couple of speedmaster heads for BBM's and they are capable of doing good power but they take some work.