Can the 2GR, 3.5 V6 Cylinder Heads be removed w/o entire engine removal? I have a GS350, but guessing the IS350 would not be much different on the answer. I have long thought no? Yes or No? Anyone? Thanks.

 

IMO - (never done it), that's a 'No Captain!'....
The timimg cover has the oil pump pickup tube bolted to it and I'm 99% certain the dowels on the heads and timing cover prevent head removal without the cover coming off. If the cover doesn't come off you risk botching the valve timing without having eyes on that chain and likely leaks once back together.

 

Yes I heard what you said. But.... you don't think removing the bumper a radiator could get the cover off with engine still mounted in? Thanks!

What has the world come too, in a day you can't just pull the heads without hoisting the whole engine out.