So I finally received my MMR 1000 short block and while I am waiting for it to be installed I am trying to figure out the best break-in procedure. I looked at the documentation that came with the block and it says change the oil after the first 400 miles (will be using a amsoil break-in oil). It also states synthetic oil cannot be used for the first 6000 miles. Why would this be? I looked at a few other engine builders and their break-in procedure said nothing about not using synthetic oil, one company even recommended switching to synthetic after the break-in period. What is your opinion? And if it’s true that I can’t use synthetic, what oil should I use while the the car is being tuned on the dyno? I’m looking to make 800-850 whp with my procharger setup on E85 and would worry about not having a proper full synthetic oil like amsoil or royal purple in the motor while doing so.