Not really, they would probably be about the same effective speed. You do gain about 10% performance going from 3rd gen to 4th gen chips.
What is this attempt with overclocking the locked processors? If you are interested shell out the extra 50 bucks for the K series and run it at 4 something Ghz.
Now there are a few vendors that have revealed that you can overclock a K series processor on a select few H87 and B85 motherboards, which would save you about $50. I laid out some options below, but to overclock you pretty much need a K series chip.
Z77 + 3570k + a decent cooler(hyper evo 212) = $370
Z87 + 4670k + a good cooler (noctua NH-D14)= $450
Z87 + 4430 = $325
H87 + 4430 = $270