If you go big block you won't have room to work on it and you'll cus it every time it needs work! You have a quality top end that's just crying for a 10 to 1 comp stroker kit. It will give you the power of the big block run on quality pump gas and fit inside the fenderwells. all you have to buy is the stroker kit and gasket set Big block or next gen Hemi will cost a lot more and take more time