My engine isn't completely done yet, and I probably won't do much with it over the winter. What preventative measures do you guys take to avoid things like rust. I was considering covering it with a garbage bag and then sucking the air out with my shop vac. Should I spray the inside with WD-40 or something?

Thanks in advance.

I make up a mix of solvent and oil, a thick viscous mix in proportion as thick as a cheap plastic spray bottle will handle & drown everything in sight. I get oil into the oil galleries also. I would leave the bag slightly open as to not trap moisture inside. The best thing you can do is store it in a heated place (if possible) so the temp does not drop down lower than the dew point (condensation)

Yes a heated storage is by far the most important during the winter. Pump some motor oil into the cylinders and you should be good. If it's sit's in a unheated shop, expect rust.

stabil makes a spray now for inside the cylinders, not sure how much it is, but it is meant for burning off instead of having to clean it like you would oil.

wd40 is not something I would use regardless.

if you could actually "seal" it in a plastic bag, you wouldn't have to worry about moisture, but I mean actually seal.
then throw in some desicant packs before you seal it and you should be good to go.

cheap "heater" 20 watt light bulb. not cfl or led, and actual light bulb.

put the motor on something to insulate it from the ground and then put a box around it with enough room for the bulb somewhere and leave it on.
use some sheet rock to insulate. should keep it warm and dry.

Bar none, this is the best stuff on the market.

LU710 made by Sprayon.

My only recommendation is to swap out the tip with another spray-bomb tip to create more of a "fog".

I've had milled surfaces stored for over eight years, and when I wiped this stuff off with mineral spirits, the surfaces looked like the day they were machined.

Its predecessor was P.D.R.P.

I buy it at Grainger for $8 a 12oz can