I personally think it should run with the 30ci flatheads with 25ci limit and a different weight rule. It's very hard for a Honda to make it to 30ci and I'm sure others too.
I agree with flatheadpuller there tons of information about them in the go kart world. There's already billet rods, flywheels, billet heads, billet side covers, dome pistons, big valves, billet valve covers, billet roller rockers, billet lifters, etc I'm sure I'm missing something!