440 Source big block aluminum heads

I've got a set of the stealth heads on my 440. I bolted them on right out of the box and picked up 4 tenths and 5 mph over the heavily ported 906 castings that they replaced. I have no idea what my old heads flow so I can't really help you out in that area. I can tell you they are a very nice product and you definitely can't beat the price.