kougar1.3 vCore is generally the max recommended, but most cooling solutions can't handle it anyway. +75mV should be +0.075v to whatever your board is using for the base voltage. Be aware some motherboards auto-overvolt so it's best to know what the final vcore number is. Be sure you're stress testing your overclocks, Haswell needs voltage to get up to 4.4 and stay stable.
advancedlambdang, surprised you can get such an overclock, my 4790k can barely even go up .1GHZ before it will crash forever