Chev 348 - 490W MSD Pro-Billet Ready To Run Distributor # MSD8393 Distributor, Pro-Billet Ready-to-Run, Magnetic Trigger, Vacuum Advance, Chevy, 348, 409, Each Distributor Cap Included: Yes Distributor Cap Style: Male/HEI Distributor Cap Type: Small cap Ignition Coil Included: No Ignition Module Included: Yes Computer-Controlled Compatible: No Trigger Style: Magnetic Advance Type: Vacuum and mechanical Ignition Box Required: No Mechanical Tach Drive: No Slip Collar: No Distributor Gear Material: Iron Distributor Gear Rotation: Standard Housing Material: Aluminum Housing Finish: Natural Marine Use: No Remanufactured: No Quantity: Sold individually. Notes: Distributor is 8.1875 in. tall from engine to top of distributor cap. MSD Pro-Billet Ready-to-Run Distributors MSD Pro-Billet Ready-to-Run distributors are the perfect upgrade for weak OE electronic distributors, outdated points distributors, and large HEIs or DuraSparks. All that's required is to install the distributor in the engine, and connect three wires and the coil! A maintenance-free magnetic pickup accurately triggers this ignition with increased output from the amplifier, easily outperforming stock ignitions. It will smooth out the engine's idle, improve starting, and perform at a much higher rpm.The housing is machined from billet 6061-T6 aluminum, using state-of-the-art CNC mills and lathes for a unit with no porosity or weak areas. For stability and endurance, an oversized steel shaft spins in a top-mounted sealed ball bearing, while an extra-long sintered bushing guides the shaft at the base of the housing. This shaft also receives a QPQ coating for low friction wear and resistance against corrosion from humidity and ozone buildup. The distributors feature MSD's adjustable mechanical advance, which allows you to custom-tailor an ignition curve to match your engine's needs. Most models are also available with a vacuum advance canister to help improve economy. Order the model recommended for your vehicle and engine application.