Hi guys......I wondered about this same issue for my suspension links and "A"arms,I have spoken to a couple of sources and the opinions are mixed. The first one was DRB cars in Brisbane when I was there a few months ago and they didn't use moly because they had seen or experienced the moly tube splitting, And another, Is Murry Gorge Engineering in NP (Well Know Modified and Speedway Saloon Car Builder) when I was there Murry was doing some top Links in 11/4" moly and miging the rodend stubs in. When I asked him about having to heat treat the moly after welding, he said he never did and even with his full moly Modified Chassis he didn't do anything after welding and there is a heap of Gorge chassis around that have never fallen to bits. So it a bit of a quandry, My opinion is do what your Budget or your opinion feels is best. My choice was to use a Tubing that is used for racing Motor cycle frames and swing arms by a custom builder here in NP I'm Not shore of the grade code but was told it was a lot stronger than Mild and no where near the Price of moly, Cheers Leonmac