Ian,

I looked up the 1600 in my parts book, and the diesel takes the same 101 410A intake manifold as the 880. The book also shows that all 1600 diesels used the same intake. The only Waukesha motor I can think of that has the intake near the front is the direct injection engine. Has his 1600 been re-powered with a later 283?

For what its worth, I don't think any of the diesels used the metal ring gaskets on the intake manifolds.