Crate motors

Im at 321k miles and preparing myself for for the possibility of having to put a new engine in this year. I dont want to be clueless when the time comes and rather be ready to pull the trigger when the time comes.

I would like to do a crate motor with a stroker. Im not sure who the reputable brands are. Also i have a cali vehicle with 5 cats and was curious if i can convert to an engine with a normal amount out cats.