'91 D150.

I have some bad rot across the top of my roof. Its weird because this is the only rust on the whole truck.

Anyways I chopped the roof off a '89 W150 and plan on splicing it on this winter. I also got the windshield.

What would you guys suggest for the gaskets?

I'd reuse the original if its in good shape.

Roof rot isn't uncommon on these at all. My 92 is doing the same.

Precision makes nice rubber

Before I'd buy from an online vendor, I'd call a windshield replacement company and see if I could just buy one of their gaskets. Sometimes they will sell it you, and you KNOW it'll work, as they aren't in the business of dicking around when it comes to installations.