Going with an I-7, that would put you right at your limit for the build.....with an I-5, you will need a mobo that isn't top of the line, resulting in you not getting the best overclocking results.....and you bolded that in your post - so that is what I took as most important.....
So basically - if you want Intel, you will get a medium to low end mobo.
I have an FX-8320 - it performs well - and will give you similar performance to most of the core i-5's out there at about $80 less in cost give you the better mobo.
The end result - you can't have a $500 build for $330.....you will either have to choose better processor and less on the mobo, or better mobo less on the CPU....