340 or 408

I know the 340 is a classic and the 408 is a torque monster. But something about the sound of a 340 spinning to 6800 rpm.

The plan was to build an aluminum head 340 with 10.25-1 compression pump gas deal with solid lifter cam. looking for 400 hp.

The Motor i am getting is a low mile 340 out of a 73-74 duster that rolled. I am not sure whats in there for components, but when did they stop putting a steel crank in the 340? My engine builder says we will use a better aftermarket rod anyway as well as a forged piston. The only thing we are missing in the end is a stroker crank. So i am torn between 340 or 408? I am spending the majority of the money anyway, so whats another $600 for a crank. The rest of the drivetrain will be 2500-2800 stall converter with 3.55 limited slip.

What is the smart way to go here?:happy1: