I bought a set of the 440 Source aluminum main caps and ARP main studs from them, my local automotive and industrail machine shop(Southward in Eugene OR) did the fitting and align hone on the 440 block my customer provided, they made the comment that they went on fine and machined well. They where inmpressed enough to ask where I got them from I'm assuming that they will buy them direct for future builds they do from now on