I'm running a similar combo with a touch less hp, but I was still able to beat a Hellcat in a drag race with it. I just swapped out a set of Schumachers poly mounts and went with a pair of stock mounts with a welded in Schumacher torque tube. I noticed that the poly mounts are significantly thicker than the stockers, the driver's side even more so nearly twice as thick. I had the poly's in the car for a few years, but didn't like all the vibration they transmitted into the chassis. They also deformed quite a bit from what I assume is heat. I tried a poly transmission mount, but that really transmitted vibration. I ended up using a HD rubber mount for my 200R4 too. I'm a few weeks away from testing the new set-up, but i am confident it will be fine.
Have you welded up your K-frame and installed the US Cartool chassis stiffening kit? It makes a huge difference in all around performance.