Short answer - probably not. In terms of strength, there's no comparison. However, there are lots of stock or OEM cast iron or cast ductile iron spindles out there that have never broken. I've got Super Bell cast ductile iron spindles on my '34 Coupe, and I used stock Mustang cast spindles on my '30 A-bone.

The chances of a Heidt's spindle breaking - when He** freezes over. The chances of the others breaking. A little more than that.

One thing to consider. Where are you going to run your car? If it's a street driver, that's one choice. If it's off road, that's another. If it's hi-po drag strip, that's another.

If you go with cast, use new ones and make sure they're not from some off-shore foundry in Pakistan or the like.