410 exhaust manifold

[Bryn Tirion]

They are heavy..... an extra 5 pounds or so!! And certainly SS ones are a viable option to consider. They aren't original though, and even with the old ones you have a 130 mph car, how fast do you want to go!?

The seldom-mentioned disadvantage of the nice, thin walled, smooth headers is that they do not dissipate heat evenly over their surface in the same way as cast iron does, and vapour lock is more likely with them, especially if your petrol has that nasty eco-fraud ethanol added to it.