My 440/493 has been in my car running fine since June 2011 and I used 440Source billet steel main caps with ARP main studs and that's all with a main cap align bore of course. Mine is a street car that only gets raced once or twice a year. Its held up great as I have had no problems at all with it and it will run 10.70's best in full street trim. I agree aluminum caps will work fine but they are not needed for your application. Good luck with it , Ron