Has anyone determined if you can swap the 2nd generation VH45 valve covers onto a 1st gen?

Not without swapping the heads. There's a groove in them that holds the gasket in place.

I didn't see a groove on the head side but I did see a groove in the valve covers.

Interesting... I was kind of guessing on the design based on the design on my old truck that had a gasket like that. I know the attachment is different - the 94-96 have studs with cap nuts to hold the covers down instead of bolts. Wild guess here, but I suspect if it was do-able it would have been done by now. Places like T3 would have been all over a method that didn't involve applying RTV.

I am pretty sure there are other differences as well. I believe the interface to the CAS is different because the 90-93 CAS is different than the 94-96.

i would have loved to have this info earlier. i hate the rtv setup, very messy and difficult with limited room. gaskets are the way to go.
did you find any info?

The early tunnel ports were thought to have a better ram effect, but if one looks at the BMW turbo motor heads, the inlets are like the later VH45DE for maximum air flow.

The later VH45DE was a slightly better design, especially if you consider the updated chain guides they included.

I've been thinking of a way to align the covers better for reassembly whenever I have to do the job again - hopefully not soon. In the FSM they show an alignment tool, but I don't know if it was ever produced. What about buying some screws with the correct size threads that are a couple of inches long, cutting the heads off, and lightly screwing them in to four of the holes in the head? This would give a guide to be sure the cover fits squarely on the head the first time without smearing the RTV realigning the cover...

Heath