okay, explain the difference between cast iron(really??) and cast steel( i think China made that up)??
Break a piece of cast iron and look at how grainy it is. Break a piece of carbon steel try to find a grain in it. Cast iron is called a "grey" metal and generally has at least 2%carbon while cast steel has 0.10.5% carbon.
A forged axle or spindle will bend in an impact. A cast axle or spindle will usually break. Somewhere in my photo archives from the mid 70's there are some photos of my 48 after a wreck with the axle bent back at a 90 degree angle. The wheel bent, the spring was a mess but nothing broke. if the axle had been cast it would have snapped in two. I could probably have taken that axle to Waco Spring and had it straightened but my buddy found me another axle and springs for a friendly price.
Nothing beats an original pair of 37-40 Ford spindles, coming in second if they're worth the effort to you are 35/36 spindles which will give you an additional 1/2 inch drop over the later spindles and finally if your using side steering the 32/34 spindles also give the 1/2 inch drop and have a forged upper steering arm. I've used all of the above on various customer chassis builds. I personally like to use MT Lincoln brakes on the front of the chassis I build both for the early looks and the ability to stop the car and they are a bolt on with some minor machining.