65-75 ft/lbs. They come loose because of the horrible soft washers Cragar supplies. Get some McGard lug nuts, they come with thick stainless steel washers.
Bingo! I torqued with tq ratchet and broke a nut (on car) at approx 85. I checked factory service manual and I believe it states 65-75.
Oh and what a pain finding new nut. Cragar SS