Engine section:
Flat crank vibration does NOT come from the firing order. It comes from the mechanical relationships of the pistons. It is a purely MECHANICAL vibration, not induced by power pulses.
I was wowed to see that the crankshaft is *NOT* fully counterweighted. By having counterweights at the #1 & #3 mains and none at the #2, the reversal loads from the pistons try to cock or cant the #2 main in the bore. If the journal makes contact with the bearing too often, it will wipe the main bearing. The crank must be very stiff to live through that. You can see enlarged cheeks of the throws around the #2 and #4 mains which would help stiffen the crank at those locations.
Also, the #3 & 5 mains are drilled (can't see #1), but not #'s 2 & 4. Drilled crank pins as well.
In *theory*, there's no difference in weight between a fully counterweighted cross plane crank and a fully counterweighted single plane crank, but a single plane crank can apparently "get away with" eliminating more counterweights than a cross plane crank can.
10:15 shows a block pictorial and the tabulated data says it uses M11x1.5 head bolt threads... Hope they used timeserts! Did they forget what they learned from the Northstar, or is the different block alloy immune to stress corrosion cracking?
Also shows LT6 has 3.5mm larger main bore in the block than the LT2... I assume this means larger main journals, which bears on the prior discussion of crank stiffness and main bearing durability.