318 Rebuild suggestions?

Yes, a 340 spec cam will fit in the 318. The cores are the same, the only reason people call it a "340" cam is due to the specs used in the 275hp 340 (or ones close to it)

https://www.summitracing.com/parts/dcc-4452761ae/overview/

I think this is it...and that's just the tip of the iceberg...there are literally dozens of grinds similar to this one which would suit your purpose.