With the cost of the 440source heads, or eddys, i wouldn't put any money into crack prowen older castings unless i was going to do all the work and already had them. There is absolutely no substitute for big cubes when it comes to street and manners in the same package. My idea of the best setup is the longest stroke you can put in the motor,if you need crank work. There are 4.5 arms out there for the tall deck block. With what you have, they will make a high to mid ten second ride out of your car because they will use up all of the head flow with a stock type port window by 6000 rpm! My first big motor was a 4.5 stroke 4.350 bore 440 making 535 cubes, with ported 906 heads. Went 10.20s at 3400 lbs, cracked the heads and i lost all that expensive porting work! Nice thing about the motor was it only needed a 5700 rpm shift point with a 590 cam . I did use a 1.7 erson rocker on the heads, which worked at those low rpms just fine and helped out the cam quite a bit.