Tune-Up Kit Mercruiser Small Block Thunderbolt | M57TBOLTGEN Mercruiser Small Block Thunderbolt Tune-Up Kit Comprehensive kit includes everything needed to tune-up Mercruiser 5.0L & 5.7L Vortec engines with Thunderbolt electronic distributors. For Mercruiser 5.0 and 5.7 liter 350 cu. in. EFI engines from 1996-up with Thunderbolt ignition systems For Mercruiser 5.0 and 5.7 liter 350 cu. in. carbureted engines from 1998-up with Thunderbolt ignition systems Everything needed for a tune-up in one convenient kit Includes 8 NGK BPR6EFS Vortec spark plugs, plug wires, distributor cap, rotor, 18-7844 fuel filter, 18-7824-1 oil filter and 8 oz. StarTron gasoline additive