Joe I'm going to suggest there is a reason leaving the brakes stock might be superior to upgrading to disks.
But first, I've seen disk brakes fail because of inferior or worn parts, and I've had them fail because they were wet. The are not immune to problems, just react a little differently.
Some of the disk conversions I've seen looked dangerous. And on a big truck, the risk of brake failure with a loaded truck is scary enough that I'd feel safer believing the old trucks out there have well-maintained stock brakes rather than back-yard engineered disk conversions.
Done right either will stop a truck and done right disks are usually superior, but I like the idea of stock drums on an otherwise stock truck over a questionable conversion.
