Basically it has been too hot this evening to do anything but after The Grim Darkness asked about Deathstrikes I thought i would get the Manticore kit out and do a quick mock up or two.
It could be made to work I think, it would mean modifying the mounting plate, either incorporating the part from the GW kit or converting a cast piece. It still won't look 'right' to me. I just don't think a weapon like this would be mounted on a gun platform.
Again it is doable with some changes to the base, but personally I think the FW Manticore turret would be much better.
I am thinking of magnetising Hydra turrets so they can either take the Autocannon or brackets holding Manticore rockets.
In other news I ordered some Earthshaker bits so that I can rebuild the one I have and put together two new ones, giving me a nice battery of three guns...