540 big block Shafiroff or Bill Mitchell??

[PSV]

Which way would you go? The Shafiroff Ultra street with the Merlin III block is a bit more money, but it makes more HP. You can get an all aluminum version from Bill Mitchell for 12,995. Are there any disadvantages to running an aluminum block on the street? If you went with the Ultra street are the callies crank and rods upgrades something I should get? This is going in a street car that will see limited dragstrip use and maybe some scca parking lot stuff. Any and all opinions appreciated. If you have had experience with a different builder in this price range please advise as well. Thanks, Paul