cast iron heads vs aluminum for stroked 340

550 hp/tq is a lot on the street. Have you had another car with a motor that has 550 hp/tq dyno sheet to back it up?

Without drag radials you'll have much more motor than tires.

An honest true 550 hp/tq 4" stroker is going to be on the raunchier side of things to fart around town and pick up groceries and take the kids to soccer in. It will be "beefy" and then some.

It's going to take ported J heads. And ported Edelbrocks too. To keep the cam streetable and still make the hp/tq.

Not sure 550 hp/tq and hydraulic cam go together. You'll still need good adjustable rockers at that lift. Probably aren't going to get enough engine vacuum to run power brakes and accessories.