400 small block ?

Hey, have a few ???'s on the 400....

Looking at doing another 400 small block(aftermarket block) and thinking about doing it in a 350 mains..... Seems to make sense. Obviously the ft/minute speed (and therefore heat potential)is decreased but one thing I would like to know is journal strength an issue on a high output motor intended for street ?

Hoping for long term streetability and brute torque strength...

Thanks for help...
-jkh