Originally Posted by Pete Burton

I hesitate to comment because my experience lies with the 617, but I expect some similarity. While it might be possible to do that in the car, I wouldn't want to. On the 617, the oil pump chain is outboard of the timing chain. Do you have another vehicle to drive for a few months? Do you have at least a 1/2 decent place to work with a poured or paved surface? If so, I'd pull the powertrain in one piece. I've done that at least 3 times and it's not too bad.

No matter what, I'd drop the lower oil pan and inspect everything. You should be able to see the crank sprocket. It's pitch diameter is exactly half of the cam sprocket. Check the oil pump sprockets and chain too.