I don't know about stalling, it can be multiple of things, idle rpm, inertia, engine resistance and torque curve (or parts modifying torque curve) can be responsible. Also torque converter size if you have automatic. Oversteering is probably because if you copy V8, that is going to be lot heavier and maybe even further forward, that means you have to have stiffer front springs to compensate that heavier weight. Check nodes from engine file and check in blender that coordinates are where you want engine to be, if it is not, then move all of the nodes same amount. Position and weight of the engine has lot of effect to handling of the car. When you add more weight to front or use softer springs at front, car oversteers more (suspension frequency changes), but also Sunburst rear suspension is not probably designed for big torque, after all it is FWD/AWD platform, so you might get bit larger toe changes under power, I think it had some bits there to simulate soft bushings for example. Compared to suspension setup, body nodes and beams are rather easy to change, when need to move suspension mounting points, that is where stuff starts to get complicated fast as moving suspension mounting points changes suspension behavior which changes handling of the car.