Starting out as solid chunks of hardened steel, these have been bred from our own racing program, and the many we are involved in. We are taking all the data gathered over the past years to present real world solutions to this platform. These main caps are able to utilize stock configuration ARP main studs, as well as our street girdle, for the ultimate in performance and longevity. We started with a MUCH stronger material than oem, provided much greater surface area contact than oem, and the ultimate ability to be wrapped up tight with a bow using our Billet Girdle to ensure that rotating assembly stays right where it needs to be at all times. No more spun bearings, no more crank walk, just raw, unrelenting power, for a very long time. Contact our sales staff with any questions! It is highly suggested to run our Billet Street Girdle with these main caps, and of course ensure everything gets properly line bored before assembly! SHIPPING METHOD DETERMINES HOW QUICK A PACKAGE GETS TO YOU FROM THE TIME IT LEAVES OUR FACILITY, NOT FROM THE TIME THE ORDER IS PLACED WITH US.