Thanks KP. I was hoping if I could get a new or repro of the same material I would cut the whole inlet side out of it an graft it into my 2 hole/no relief box. Figured that would give me superior strength where the carb manifolds go in. I thought Yamiya made one a while back but I only see two materials on their site now.
Guess I'll have to get creative!
I found what I was looking at. They have ABS sidecovers.