Zip,I have a set of both Comp and Red Zone sbc lifters.The comp tie bar will come off by turning the lifter 90 deg and just removing it,The Isky looks like you would have to grind the flatened end of the bolt and then remove it with an allen.The comps all the way spred apart are 1.700 centers on the tie bar button head bolts.If another masurement will help let me know.Bill