Assuming you are running on a smooth flat surface, you many want to raise the ride height to avoid bottoming out the car over bumps/dips/pavement irregularties.. You may also want to put some fuel tubing on the shock shafts to also prevent the car from bottoming out.
Another thing to look at is making sure the body is mounted securely and the wheels aren't rubbing anywhere on the body. It is possible that when you went full throttle, that the wheels are ballooning up and rubbing the body causing the spin. I'd recommend using belted tires to prevent this.
Ride height and body/wheel clearance are critical at the speeds you are trying to achieve, because the slightest chassis/wheel rub will cause erratic handling issues.
Above all, good luck and have fun.
I'm currently racing VTA. Check here for rules/info: http://www.usvintagetransam.com/