Buy a 4" dropped axle. The original model A front axle is way to high, and is not spindle friendly. Model A axles are rather anemic, having been originally designed to hold up a small 4 cylinder engine. An aftermarket axle is intended to be used with a large heavy V8. Also, aftermarket axles can be ordered to accomodate a number of different spindles, giving you the option of disc brakes if you want to go that way.