I'm putting the heads on my 408 build in the next couple days, but I won't get to fire the engine for a couple months most likely. Should I coat the cylinder walls with oil or something else before I install the heads? Or just clean them up and put the heads on them dry?

 

I'd coat um with oil and turn it over a few times then be sure to block off the spark plug holes intake ports and exhaust ports.

 

I usually keep mine coated when the heads are off as the area where I am will result in rust within days if I don't. I would coat well and turn it over cleaning any oil that comes out onto the deck real well prior to putting the gaskets in place.

One other option is you could leave them as they are, install the heads, and then use Mercury Marine storage spray. Normally, it is put in with the motor running. However, I have used it through the spark plug hole. I like this spray because it will foam a little when it comes out and it coats everything pretty good plus it burns right out on motor start.