Also, I was just planning to buy the two head gaskets from Autozone (not the full set). Is this fine?
Don't go buying parts just yet. This sounds more like valve guides than cracked heads, although it's pretty much impossible to tell because "white" and "blue" smoke can look pretty similar.
My test for valve guides and seals is pretty simple: does it smoke more after driving it at cruising RPM and then coming back to idle? The warm up thing points to worn guides, more than head gasket barring any boil-overs (which are the number one pointer to a blown HG or cracked head). Worn guides allow oil to be sucked past the intake valve in high vacuum such as when the engine is returning to idle while driving.
You need to change the head gaskets, buy a head set - since you have to remove the intake manifold, exhaust manifolds, valve covers and likely the valves if you want to pressure test and surface the head (strongly recommended).
With that said, I wouldn't even bother disassembling the crap stock heads. You can typically find a good set of rebuilt heads on Craigslist for what it costs to inspect your stock heads for cracks, and surfacing them.
And for what it costs to rebuild stock heads, you can buy iron performance heads brand new in the box. If you're really good you can peruse Craigslist and locate some killer aluminum heads.
Let us know.
