I am starting a complete renovation of old blue.  On aprox a 70-75 HP motor is chain breakage a problem.  Can a 530 chain be put on these. I dont know if sprockets are available to fit the zilla----your thoughts and experience???

Custom sprockets will need yo be made. 530 stamping with whatever tooth count you deaire than the lt500 broche will be stamped. Than you will have to deal with the width of the 530 chain hittting the cases.  Remember a 530 chain will ride on 520 sprockets but a 520 chain wont fit on a 530 sprocket.

They dont need it. A few 100hp singles out there still running 520 chains.

Exactly what i run on my liger. got it from m&m atv online. Sell it by the foot. Like an 8-9k tensile strength.

one of my bikes that i run in the sand uses a non o-ring chain
i dont ride in the sand that much just a few times a year, but i do ride the same bike
in the woods and i have not noticed any signs of wear.

I dont ride in sand but mud and dirt yes and inever use oring chains waste of money imo a GOOD non o-ring will out last a o ring in dirt but i could see sand wearing it faster not being sealed.