The aluminum Pond block has been recently improved to strengthen the main web area. It still uses the basic sideoiler oiling system, is not available with a big bore option like the Shelby block, and the head studs don't extend as far down into the block as the Shelby block's do. I like the Shelby block better due to the oiling system, head studs, and the availability of a big bore option, but I don't know if it's worth the extra $2K. The Pond block ought to be good for at least 1000 HP in it's current configuration. If I was buying a new one, at this point I think I'd go with the Pond...