Maybe. You’re recommending it so show us the results from your testing. I’m saying there are diminishing returns with regards to moving the cam that far.
Yes, all to familiar with emissions testing. But I still wouldn’t go through the hassle of advancing a stock cam 2-4 degrees. I’d just put a different cam in it.
I probably would put a different cam in it too. With him seemingly only going to replace the chain I thought why not advance the cam. He probably wouldn't notice the difference