Why not build a 340?

I started rebuilding my 318, I messed up doing the ridge reeming, got too deep into the bore. So I'm doing a complete rebuild now. May have a 340 short block available for a good price. My heads are all rebuilt, ported the head. Planning on using the 318 heads. Ya, I know, not the best route but it's what I have. Can change out the heads later. But why not a 340 instead of a 360? I don't have the money to build an expensive engine. I just want a decent hot rod. Already have new 268 cam and lifters. Performer intake with edelbrock 600 (Carter copy). Doug's ceramic coated headers.