Engine dyno software. Anything good on the Internet?

I'm all for rounding off 1% on a simulation, but that's not what I'm talking about.

But for example the difference between a 230 @ 0.050" hydraulic cam
and a 230 @ 0.050" solid cam

... is HUGE.

I once read something to the effect of "When changing from a hydraulic to a solid cam, add 10 degrees @ 0.050 to get similar valve timing to compensate for lash"

The range of duration in typical aftermarket cams from mild to wild is quite small.

For simplicity's sake

So let's say that a small cam is 200 @ 0.050"
and an extremely large cam is 270 @ 0.050"

70 degrees. from (more or less) one extreme to the other.

If the simulation is ignoring that (approximately) 10 degrees @ 0.050 that is taken up by lash with a solid cam, the entire torque curve is going to be balls up.

Just my opinion.