[Tazimafied]

This is something common in high performance engines that have high compression and advanced timing. I would check the timing first to make sure it isn't too far advanced for your setup. If it is where you want it to achieve the desired performance then I would check the starter next. It could be just old and weak enough to not be able to turn the engine over when hot. If the starter is fairly new I would recommend upgrading to a higher performance unit.