The .70 engine rips the car it came in apart. Pretty much unusable. The GST is much sturdier, so it could handle it. It's ridiculously big though. I'm guessing some mods would be required, but with a drill and the stock Thunder Tiger .70 mount you'd be good to go.

You should test the MGT 8.0. It's slightly larger, so I'm not sure if you can drop it right in though.