Can I remove the cylinder heads on a 3.5l in the vehicle? on 2007 Toyota Sienna

I have a 2007 Toyota sienna 3.5l. I get a massive plume of blue smoke when I start it in the morning and occasionally on acceleration. I'm thinking valve stem seals but I've heard you have to drop the power train out from underneath to remove the timing chain. Can the heads be pulled without dropping the engine out?

Asked by for the 2007 Toyota Sienna