stainless exhaust manifold caps?

[techbod]

The steel 5/16 caps that the previous owner put on the exhaust manifold (xflow) are starting to rust quite badly so I'd like to replace them.

 

I've bought some replacement SS versions, but looking through the archives opinion seems to be divided about using SS - it seems it might harden through heat cycling and become brittle? Also is it more or less likely to seize?

 

Can anyone confirm (or deny) that this is the case and if so what should I be using instead? Should I use studs instead with brass nuts?

[Drumster]

I used s/steel capheads on my x/flow exhaust manifold and don't recall there being any problem, however, that doesn't mean it was the correct thing to do. So hopefuly someone can confirm or deny?.......

[techbod]

Thanks for the reply.

 

Partially answering my own question, it might be very tricky getting nuts on the middle two with studs as they are very close to the exhaust. Probably the reason for using caps.