Hello again,
I have done this exact procedure on my Ford 4.6L engine, but I replaced an entire cylinder head and I was able to just redo the one timing chain, because they are keyed and I knew the other side was right. Having said that, to make absolutely sure that your timing chains are spot on where they should be, I would recommend that you reset them on both heads. Your timing chain cover should be off anyway, and it shouldn't be that hard to set your crankshaft and two camshafts in their proper spot and run the chains. You are going to be there anyway. I will send you the factory guide on how to do this correctly in a couple of minutes.
Thanks,
Alex
2CarPros
Saturday, July 6th, 2019 AT 1:11 PM