Chevrolet 396 Big Block - Mean Little Rodent

With the deck squared and zero deck height set, our machining wonder-boy Dave Akard, who also happens to own Burbank Speed and Machine (BSM), goes to work on the cylinders. Dave first bores the block 0.060-inch over to give us a displacement of 408 cid. Dave's crew will finish the bore preparation with a Sunnen block hone.

Here's a secret piece of junkyard gold. Although all records of what vehicles they originally came equipped in have long since vanished, we know that some 366-cid truck big-blocks came with stronger connecting rods (right). These rods are the same length as stock rods, but feature a much beefier big end. We paid $80 for a set and had The Balance Shop polish and shot peen them before balancing.

Since we knew this engine would see 6,500 rpm often, we choose to replace its cast crank with a forged GM crank The Balance Shop sold us this one for $75. Dave Kemblowski, owner of The Balance Shop also balanced the entire rotating assembly.

With the freshly machined crank and block back in our possession, we thoroughly washed and checked each part for machining accuracy. Even though we trust our machinist's abilities, you can never be too careful when it's your parts on the line.

Here's a tip for any 396-cid big-block. The top of the cylinder bores are plunge-cut at the factory to clear the intake valve as can be seen on the left side of this photo. We like to radius that sharp cut with a die grinder to further unshroud the intake valve in the cylinder. Also note that we scribed the head gasket's bore on the deck surface to keep us from grinding too far.