340 Build Spec's

Since you are deviating from stock anyway 360's are much more plentiful and a bunch cheaper than a 340. Comparatively built, the 360 will make more power at a lower more street friendly rpm than a 340. You can always dress it out with a 340 pie plate on the air cleaner, the only way anyone would know is they crawled under the car and looked at the casting numbers on the side of the block. Think of it as a stroked 340 (which is what it is).

Or, you can take that 318 you already have and rebuild it with the MP 4" stroker crank and have a 390. For sure you will need to replace the 318 heads with 340/360 heads.