Slant 6 balance

If it follows LA crank register size change, its 68 and up with the 1/4 larger bore up to 68 was smaller bore. As for balance of a 120 degree 6, there is none externally as i remember. The design of a 120 degree straight 6 is 'natural' meaning of the crank is undisturbed and the piston and rod packs are all neutral balanced, there is no external balance needed. Like a 4 banger as long as the pistons and rods match, its self balancing. Most slant 6 dampers have a straight line cut out the back side. Not sure what this is for but they all seem to have it. V8 is a lot harder to balance as the re are other forces at play being a 90 or 60 degree offset. 5 cylinder inlines are just weird. I think they are flat plane 180 cranks but the turbos dominated the rally world in the Audi Quattros I think the were classed out.