This is the way I do it... Bolt the core support in place loosely, then lay the inner fenders over the tires & insert a couple of bolts that hold the front of the inners to the rad support, just hand tight. Then mount the main fenders loosely in place & hand tighten a few bolts. Then attach the inners to main fenders, again hand tighten a few bolts. Now set your gaps & install your shims... Once you have everything where you like it, start tightening the main fender bolts first...then snug up the inner fender bolts. Just remember there's a few bolts on the front that also are used for the valance & the inner fender extensions, so if possible bolt those up before tightening everything.