The longer stroke puts added stress on the block. Since you're spraying it I'd rather see a stock stroke (forged crank) or 3.79" stroke. The more inches you run, the better the heads need to be IMO. I think you'll make more power with the 4" stroke and better heads than you might on the longer stroke crank with slightly less expensive heads. Of course if you can afford the longer stroke AND the better heads, that's a different story altogether. Course you're only shooting for 500 hp. You could do that with stock stroke and a hydraulic roller cam. Some ported Edelbrock RPM Magnum heads. Spend the rest of the money somewhere else. The stroke will translate into more seat of the pants feel though. Guess it depends on what you want.