actually studs are not factory,the head bolts on these motors are notorius for "stretching"under higher comb cyl pressure(ie..using a tuner,high boost,etc)which causes head gasket failure.arp makes a head stud kit that you can install or have installed,and if you read previous posts,id reccomend this.especially if your gonna play with your 6.0.stud kits runs 400-500(i think)if your abe to do thge install it would save you alot of money.if someone does it for you id expect at least 2000 to do the job.6.0s are not mod friendly right outta the box be careful.....good luck charlie