Question on 4.2/4.0 Valvecover swap

I want to swap a Clifford 4.2L aluminum valve cover over to my stroker. I believe it should be a good swap but have no personal experience. I know that the vents are slightly different but I can deal with that. My biggest concern is the mating flange and how tall it is.

Does anybody have experience?

I was googling and reading threads from guys who put 4.0 heads on 4.2's, and it appears the bolt pattern for the valve covers doesn't match, so it won't work.