I agree with you about a 292. I put one in my 61 Apache K10. I love it. A 292 won't fit in a COE. It's too long, it's too tall and the big gotcha is an updraft intake, don't think there is such a critter for a 292.
I'm not really sold on the build either. If you want a 261 with more cubic inches, just buy a 292. Way more reliable, alot less machine work involved.