Tall deck blocks are worth considering. They all came with forged cranks but used short rods to make room for 4 piston rings. You can use longer rods with the stock crank and some normal pistons to make a very torquey engine. You can also use the rods that came with the block and a stroker crank with some normal pistons to make a very torquey very large displacement engine. It is the same block that GM uses to make the 572. Normal intake manifolds will not fit, but there are many manifolds for tall deck blocks available as well as adapters.