I would go with the longer[6.385] rod even on a cruiser.The advantages over all would be worth it.Unless you're planning on a high rpm,high horsepower engine,there's no need for the H beam rod.Have the block checked for bore taper and out of round.Also,before you pull the pistons,measure the deck height for evenness as it's not uncommon for there to be some twist.Make sure that the block at all four corners is square.For 400,some head work with bigger valves,a small cam[something in the 224 in.,230ex.@.050 range],an Edelbrock small port single 4bbl.intake,a carb of around 750 cfm,and a small tube full length header and you've got an idle-5,500 power band daily driver reliable engine that isn't bad on gas once you get it tuned out.Your street tires will hate the torque [FUN] that this combo will make.