What RPM should I shift at?

Did several runs at the Mopar Nats last weekend. Tried a little of what I read here and found the the best MPH was shifting around 5700 RPM. ET times were also a little better. Ran fairly consistent times of a 14.68. Guess it's ok for a 100% stock car. I am now on the fence about just dropping the coin and ordering an engine from Blueprint. Thanks for everyones input!!!