I have been trying to do some research on Cross Rams. I first thought that the one I found in the 69 AMT Barracuda kit (with the extra bumps) (never figured out what the bumps were for, all the pictures shows them plugged??) were the type used on the Hemi.
and the smooth ones found in the AMT Roadrunner and GTX kits were used on the Max Wedge engines
After looking at a bunch of photos I discovered they were used a lot on either engine.
I found other variations that seem to be aftermarket versions and nothing at all that looks like the one in the 49 Merc kit.
If anybody has more info or a web site with more information I would very much like to hear it.