Yup like he said there, with a 4k governor spring you;ll need to upgrade the valve springs to 60lb HD springs. or you'll be tempting a valve to float and kiss a piston.without specialty tools the timing isn't easy at all. The governor springs aren't bad but time consuming. I assume you are doing heavier valve springs too with the 4gsk. Pther stuff wouldn't be too bad just have to know where to turn what, but sometimes it's just easier to have someone else do it.