Nah, the valvetrain will be plenty stable up to the 3200 rpm peak.:lol:
I do actually have a set of ported 974s with 2.055/1.625s that were 279 at .500 and 281 at .600. They're a bit leaky after a season though. Still, it would be interesting to see how much power they would make on a combo like yours. Not inferring anything, just thinking out loud.
If I see something that might be of interest to you Mike, I'll be sure to pass it on.