Max RPM on mostly stock 400?

All good info, thanks guys. I'm glad to hear that I can safely bring the RPM's up a little higher while the engine's still pulling strong.

It did get a new timing chain with the cam swap and engine rebuild, I'm just worried that it's a single, non-roller type and I'd feel much safer with a double-roller type.

As for the valve springs, I'll probably add some stiffer springs later when I change to roller rockers. Still eying a new set of heads too though, so who knows when that will be.

Hell, I don't know, I'm still looking at the Hughes whiplash cams as well. Maybe I'll end up adding one of those with a double-roller chain and some stiffer springs. Get it done all at once that way.