Tunnel ram or no tunnel ram...

This is Indy tunnel ram without cover after initial cleaning. I was thinking about spacer under top cover but this is for future experiments. No room for anything in current setup.
I was asking about filling that void based on this plenum design.

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I was looking to see if I posted my Modman "tunnelram" on this site and I found this older thread. I'm not sure if you read in my earlier response to you that I do have a downward slope in these cavities to avoid puddling. Further, Indy's design of this plenum and runners is not terrible but it's not ideal.