383 Torque Monster Build

The two most important things with building a 383 for performance are block machining, and piston choice. The block's cylinder decks are always much taller than the blueprint spec. For the numbers guys, decking the block on any of the old horizontal millers usually means removing the ID stampings... So it's best to find a shop that has a CNC mill that can properly cut the decks without losing the numbers. Then, have the block blueprinted at least. At most, take the piston you want to use, determine the correct deck needed for your plans, and have it cut to that height. Most pistons are short in compression height. So you can end up with a domes piston that struggles to reach 9.5:1 static. The factory Hi Po pistons don;t help either. So buy great pistons, and have the block prepped by a performance shop with good modern equipment, and you're on your way. A 9.8-10:1 383 with open chamber heads and the right cam will make 400hp easilly with similar torque figures. It's not an RB stroke, but it will make RB power on pump fuel.