400?

The perceived rpm capability of a 383 is not relevant. A properly prepped 440 or even 500 cube stroker can rev quicker and higher than an old school 383. It's all about the combination of parts. If you don't already have the intake, step up to an Edelbrock RPM, as it will beat the streetmaster everywhere, including the lower rpms. Either way, a 400 will work very nicely for that setup. Good luck on the build. Should be fun.