Which of the two are better for exhaust manifolds, im guessing the stainless steel right?
Cast iron. That's what OEMs use obviously it's better. Bring on the Thumbs Down from the peanut gallery.
I would go with the stainless steel. I know that there was recently a study done that said that the non-stick material is slowly leaking the non-stick coating into your food. There is a problem with the copper and other metal pans as well. Slowly poisoning you throughout the years. As far as the cast iron, I am not totally sure that there are any problems with those. I haven't heard anything about them that is. I do know that cast iron gets hotter and cooks faster than the other metals. I hope I was able to help. Good luck.
For strength, cast iron (that's why OEM exhaust manifolds are made out of it). For performance, stainless steel. For one, stainless steel headers are lighter than cast iron ones. Then they come in multiple arrangements, (4-2-1 or 4-1 for 4 cylinder motors). The down fall is strength. Hit a pot hole with the collector of a stainless steel header. It's going to have a nice dent in it.
