Spun a bearing in my 02 gt the other day and going to replace with a craigslist engine. I plan on replacing the intake, oil pan, valve cover, and timing cover gaskets. Does anyone recommend i change any other seals/ sensors, etc. before it goes back in? I was going to replace the valve seals but have only messed with 4.6l timing once and that was 13-14 years ago lol so my memory is alittle rusty. If i were to replace the timing setup and valve seals, do i need these specialty tools to set piston at tdc and hold the cam from moving? Or can i make a few marks on the chain to line up with factory alignment markings?