The first rocker that broke (#4 exhaust) broke on launch, as soon as the transbrake released. I have launch RPM set at 3800. The engine had been warmed up prior to making this run. The second rocker (#5 exhaust) broke shortly after initial launch. However, on this run the car made a hard right turn (something it has never done before) so I got out of the gas until I got the car straightened out and then I got back on the gas while still in 1st gear (powerglide). The rocker broke soon after getting back on the gas and may be due to my pedaling of the throttle. Again the engine had been warmed prior to the run. I shut off the engine immediately, thru it in neutral and coasted down the track and got towed back to my trailer.