what is the best small block and why ?

that helps alot the car is going to be built for the street. just looking to build a tough street car and maybe go to the track a few times. i do have a line on a 340 complete needs rebuild for 500 dollars could i get a 360 for that price and the 340 is a 1972 block is that a good year and are all 340s 10.5 to 1 and with what heads