Are 340’s rare

I have owned a factory 340 car since 1983 and it will remain a 340, as it should. BUT, I have long advocated (since before I owned a Mopar 340 car - I did own a non-Mopar 340 car once upon a time) for building a 360 for a street performance car simply due to the cost difference and ready availability. This was also before most people figured that out. If I had another original 273 four barrel car I'd build the 273, but I don't see an application for a 318 in my world. Due to the relative rarity of the 340 vs. 360 there will always be a price difference.