The MT2 is a 1/10 small block truck so you can't just drop in a big block without modifying the drivetrain. My 1/10 4WD ST is able to fit a non-pullstart big block but I don't think my drivetrain can handle that power. If you going to do an engine swap, then I'd suggest hardend steel diffs, metal or thick nylon spur gears, and also if you can, get some thicker dogbones. But are you shure a big block can fit without chassis mods?