Crate engine for 78 350 CA truck?

[charlieatthedisco]

Tried doing a search for this because I'm sure it has already been mentioned but the search always fails on me. I was thinking throwing in a crate engine in a 78 c10 which already has a 350 but is tired and needs a rebuild. I'd rather start fresh. What engine do you recommend and from where? also would I be able to add all of the smog components to it that I have on the current 350? It is a CA truck and must be smogged. I'm not looking for major HP gains here just a driver