For all the messing around with other ways to go single, sealing the stock plenum, making straight runners, and a top plate to mount the carb is probably the simplest and is proven to work well. I have the means to make such a setup out of sheet metal that looks good and doesn't require a tube of sealant to make airtight. It would be an easy swap. I'm going to work it up and see what it would cost to make. I'll probably make one for myself but I'm curious if anyone else would be interested. Heck if you already have an OEM plenum and tube rig in place it would be even easier and you'd never need to worry about leaks again.