Did you drain all of the coolant before pulling the heads? It is not uncommon to get coolant in the cylinders when you remove the heads if you did not remove the drain plugs from the block. As long as no coolant gets into the crankcase, you should be fine. Of course you need to change the oil and filter before starting it up, and again after breaking in the cam. When draining it the first time, look for signs of coolant in the drain pan, the old saying "oil and water don't mix" is evident if there is coolant present. As Oldkimmer said, it is imperative that you get ALL of it out of the cylinder bores before reinstalling the heads, also wouldn't hurt to wipe down the cylinder walls with oil too.
