Chev 250 68-72 Engine Long Block 4.1L

General Information
• Core value not included.
• All engines come with all pictured components.
• If no pictures are available, engine will come as a long block with no tin ware, all gaskets, and new oil pump.
Engine Blocks
• Each case iron block is magnafluxed for cracks and checked for any visible damage to the block or threaded holes before being repainted to the original color.
• Five CNC machining centers that are programmed to precise specifications that meet or exceed those established by the OEM for each block.
• After the engine block is bored, decked, and chamfered, each cylinder is honed with the specified cross-hatch pattern.
• Quality audits are performed to ensure that the cylinder size and finish meets specifications.
• 100% new pistons, rings and bearings are installed in every engine.
Cylinder Heads
• Every head is resurfaced and completely inspected for any visible damage or cracks.
• Valve seats are machined, inspected and replaced, if necessary.
• Valve guides are inspected with an air gauge and replaced if necessary.
• The cam bore is checked on overhead cam engines and machined if required.
• Only new valves, seals and lifters are used in every head.
All plugs and fittings are replaced with new pieces to protect against possible coolant leaks.
Connecting Rods
• Each connecting rod is measured against OEM specifications for bend, twist, and center-to-center length before use.
• The piston pin bore and bearing bore are measured with air gauges for proper dimensions.
• New torque to yield rod bolts and nuts are installed.
Crankshafts
• Crankshafts are machined on a fully automated Jucrank CNC crank grinder. This enables to maintain consistency and critical tolerances for each journal.
• All oil galley holes are chamfered and brushed after machining and the crankshaft is given a final wash to ensure cleanliness.
• Each crank is inspected for cracks, bow and all applicable run-out specs for rod and main journals.
Visual:
• 100% visual inspection, sorting and grading of core during tear down.
Crack Detection:
• 100% magnaflux inspection of all block and all cast iron cylinder heads.
Air Gauging
• Cylinder Heads – 100% gauging of valve guides on all engines. 100% gauging of lifter bores, and cam bores on all OHC engines.
• Crankshafts – 100% gauging of all rod and main bearing journal diameters. Each crank is inspected for cracks, bow and all applicable run-out specs.
• Connecting Rods – 100% gauged for: bearing and pin bore diameters, center to center dimensions to measure rod stretch, rod bend and/or twist.
• Block – 100% gauging of all cylinder bores for diameter and roundness after final honing operation.
Dial Bore Gauging
• Blocks – all crank main bearing bores and all cylinder bores measured for diameter and distortion.
Vacuum Decay Testing
• Cylinder Heads – All head and valve assemblies are quantified for leakage using a vacuum decay process.
• Pressure Decay Testing of long block assemblies
o Coolant passageways – all engine assembles quantified for water jacket, head gasket, and casting leakage
o Oil passageways – all engine assemblies quantified for oil gallery, gasket, and casting leakage.
• Dynamic Engine Testing
o Sims Testing – all engines are cold motored and checked and measured for proper torque to turn, cylinder compression, oil flow, oil pressure as well as audibly monitored for any unusual noises. All sealed units are testing for oil and coolant leaks.
o Block – 1 block per engine family is laid out and checked for all critical and high impact characteristics as defined in our control plans. These measurements include surface finishes, surface flatness and cylindricity.
o Cylinder Heads – 1 head per engine family is laid out and checked for all critical and high impact characteristics as defined in our control plans. These measurements include surface finishes, and flatness.