A cut off sock will work (using the upper part) to slip around cylinder too hold enough heat in to help your engine to warm warm up more even.. I would sure do that on a new engine. A cold breakin is just inviting trouble. The back of the cyl would heat up a lot faster than the front of the cyl. Depending on how cold it is ..with.the thickness of the sock in mind...mabye you could leave it right on the cylinder. Just note how warm it gets & adjust as needed. Kinda like In the winter I block off the air with cardboard on my truck. Just watch the temp gauge for good measure. Big deisel trucks as you know close of air flow too for more thermal efficientcy. Shoot I can,t spell to good.....I did have spell ck...now missing? Oh well close enough!

Capt,n