How can you tell by looking at a GM part if it's cast or forged steel? Are there any clues to look for? Can you tell anything by running a file over it?

 

cast parts will have a seam somewhere on them where the two mold halves were put together,forged will not.

 

Thanks for your reply Atomic. I always thought that too, but a friend told me that when the forge slams down on the parts that it also leaves a parting line so I'm wondering if there are any other ways to tell the difference.

 

There is a line, but its much wider. Often times its like 1/4 to 1/2 an inch.

 

OK thanks. That makes sense. I've seen that on the forged versus cast crankshafts.