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Replaced Engine Mounts - Still Some Rattle. Normal?

  172 Cup
Hi Guys,

I have a 172 cup and the engine mounts have totally had it. In every gear when pulling hard, it would judder and shake. This weekend I replaced the lower mount (dogbone) with a powerflex poly-bushed jobby and the upper left (next to cam cover) and upper right (under battery) with OEM mounts. This has mostly fixed the problem (hurrah!). However, it does still shake a bit under certain circumstances...

If I gun it hard and smooth (eg foot flat all the way from 2k to the red line) there is no rattle. However, if I gun it, then ease off and then quickly come back on full power (eg, boot it in second to 4k, totally lift off for a second, then floor it again to 6k), after I lift off and come back onto the power it shakes like a b*****d again all the way to the redline. It will go away once the engine settles again and I am smooth. Basically, if I am on / off / on / off the power hard then it rattles, if I am smooth it doesn't.

Is this normal for the OEM engine mounts or may I have a problem elsewhere - exhaust mount or something?

  172 Cup
Also, how much should you be able to rock the engine by hand? I can move it about 2-3 cm, not quite far enough to touch the rubber stop blocks on the left side engine mount (by the cam cover). Is that about right?