Im pretty sure ARP's bolt kit isnt even for our late model engines. My best advice is so go to home depot or lowes, get some grade 8 replacement bolts. Im assuming the threads are corroded....which sucks for trying to figure it out at the store. But you should be able to get pretty damn close between a couple new bolts to take home and try. Then just return them and get the rest of the lengths you need based on the corroded bolts you have in your hand.
You may get lucky searching the multiple forums trying to find the thread/pitch....and you know the length. So then you are all set.