Exhaust elbows for '83 48MY

[Buccaneer]

Yup, I'm messing around in the engine "room."
The exhaust RISERS (not elbows, not aftercoolers) need replacing. Thoughts on where to go for new ones? (DD 6v92TAs)
(I'm figuring Sams isn't going to have two "in stock" - ya know...)

I've got "helpers" who are - some more, some less - mechanical (I'm not). Can this be a DIY project?

[REBrueckner]

How do you know they need to be replaced? I don't doubt you, but am interested to know what symptoms you see.

Usually the biggest problem with non water cooled accessory bolts is that the bolts sometimes break instead of turning loose...There is likely at least one thread here that discusses some removal techniques to help avoid that ....I remember some discussion but not the subject/title....

[Buccaneer]

The RISERS have been rusting away for 10 years or so. (Owner before me and owner before HIM) all saw it, all "let it go." Reputable engine mechanincal surveyor noted exhaust leaks, and we figure it's only going to get worse. (I tried to put it off should have dealt with it sooner...)

I'm getting quotes anywhere from $5,000 to $13,000.