fox222, I run big blocks in my car with some similar problems. However, I upgraded my drivetrain to all heavy duty parts along with cvds all around and a 4.5mm t7075 aluminum chassis. I have not had any problems since then. I think I know your problem. You are probably not running tall enough gear ratios on your car. If you run tall gear ratios, the engine's power will be smooth out, resulting in less force during take off. I run a 26t pinion x 39t spur gear single speed. For your situation, I would recommend you running hpi 19t red pinion (gear 1) x 23t red pinion (gear 2). Also, you should upgrade the spur gears to 39t (gear 1) and 43t (gear 2). This will give you more top speed and keep your drivetrain alive. If you have a dremel, you can run 37t spur gear 1 x 41t spur gear 2. You will have to use your dremel to make the engine mount holes on the chassis a little bigger. I ran an .18tz AB Stage 2 modded in my rs4 in the past and with super tall ratio, the engine only snapped one dogbone and that was it. I am currently running an Orion .21 onroad CRF REV in my rs4. Great engine with amazing rpm. Good luck to your project. Let us know how it turns out.