how bout 560 ci.
SBC block, built to accept BBC heads...
In the market for a rather large cubic inch Small Block Chevrolet? Well look no further than PBM Performance Products, who pulled the wraps off their new 4.840 bore spacing aluminum block in Indianapolis that’s based upon the famous SBC but has been stretched in every vital area to provide a block capable of upwards of 560 cubic inches. In doing so, they’ve also made all of the internal components less crowded and more like that of a big block.
Weighing in at 124 pounds, this new block features a larger bore spacing and a modified cam tunnel, with more overall room for components without excessive machining. The maximum bore size is 4.550″, with a 350 or 400 main journal size, and clears up to a 4.250″ stroke. Made of proprietary 356 T-7 aluminum, it also features a raised camshaft location, 9.000 to 9.600 deck heights, dedicated main oil system, ARP hardware, splayed center main caps, and a 6-bolt rear main cap. The standard SBC water pump, fuel pump, and distributor will bolt right up to this block, making it easy to work with, and it will also accept any Big Block Chevy cylinder head. New cylinder head designs specifically for this block are in the works, as well.
link
SBC block, built to accept BBC heads...
In the market for a rather large cubic inch Small Block Chevrolet? Well look no further than PBM Performance Products, who pulled the wraps off their new 4.840 bore spacing aluminum block in Indianapolis that’s based upon the famous SBC but has been stretched in every vital area to provide a block capable of upwards of 560 cubic inches. In doing so, they’ve also made all of the internal components less crowded and more like that of a big block.
Weighing in at 124 pounds, this new block features a larger bore spacing and a modified cam tunnel, with more overall room for components without excessive machining. The maximum bore size is 4.550″, with a 350 or 400 main journal size, and clears up to a 4.250″ stroke. Made of proprietary 356 T-7 aluminum, it also features a raised camshaft location, 9.000 to 9.600 deck heights, dedicated main oil system, ARP hardware, splayed center main caps, and a 6-bolt rear main cap. The standard SBC water pump, fuel pump, and distributor will bolt right up to this block, making it easy to work with, and it will also accept any Big Block Chevy cylinder head. New cylinder head designs specifically for this block are in the works, as well.
- Stretched SBC capable of upwards of 560 cubic inches
- Made of proprietary 356 T-7 aluminum
- Features 4.840″ bore spacing and enlarged cam tunnels
- Standard SBC water pump, fuel pump, and distributor bolt right on
- Compatible with any Big Block Chevy cylinder head
link
But I agree with rene and stomis, get an aluminum big block and roll with it. 
