However, if you are experienced and determined to do this yourself, here's a general outline. This is a *simplified* overview and doesn't cover every detail. Consult a detailed shop manual specific to your year and model F-150 and 351M engine for precise instructions and torque specifications.
1. Preparation:
* Gather Tools and Supplies: You'll need a complete set of metric and SAE sockets, wrenches, torque wrench (calibrated!), head gasket set (including appropriate head bolts/studs if necessary), head bolt/stud lubricant (never use oil!), sealant (if specified by the gasket manufacturer), engine hoist or crane, engine stand (if removing the engine), cleaning supplies (brake cleaner, degreaser), feeler gauges, straight edge, and a shop manual.
* Disconnect Battery: Always disconnect the negative battery terminal first.
* Drain Fluids: Drain the engine coolant, engine oil, and transmission fluid (if applicable).
* Remove Accessories: Remove the intake manifold, valve covers, distributor, alternator, power steering pump, air conditioning compressor, and any other components obstructing access to the cylinder heads. Carefully label and organize all parts.
* Remove Cylinder Heads: Carefully remove the cylinder heads using an engine hoist or crane. Be mindful of the head gaskets themselves as they'll likely be stuck to the head and/or block.
2. Cleaning and Inspection:
* Clean Cylinder Heads and Block: Thoroughly clean the cylinder head mating surfaces on both the heads and the engine block. Use a scraper, wire brush, and appropriate cleaning agents to remove any old gasket material, debris, or corrosion. Inspect for cracks or warping. Any damage necessitates repair or replacement of the heads.
* Inspect Head Bolts/Studs: Examine the head bolts or studs for damage or stretching. Replace any damaged or questionable bolts/studs.
* Inspect Cylinder Block and Head Surfaces: Check for any imperfections on the block and head surfaces using a straight edge and feeler gauges. Even minor imperfections can cause leaks. If necessary, have the surfaces machined to ensure a perfect seal.
3. Head Gasket Installation:
* Apply Sealant (if required): Apply sealant to designated areas on the block (if specified by the gasket manufacturer). Follow the manufacturer's instructions precisely.
* Install Head Gaskets: Carefully align and install the new head gaskets onto the engine block. Ensure they are properly seated.
* Install Cylinder Heads: Carefully install the cylinder heads onto the block, ensuring they are properly aligned.
* Install Head Bolts/Studs: Install the head bolts or studs and tighten them in the proper sequence and to the correct torque specifications as outlined in your shop manual. This is critical to prevent warping. Use a calibrated torque wrench and follow the manufacturer's torque sequence diagram. Often it's done in stages, increasing torque in incremental steps.
* Reinstall Components: Reinstall all the accessories, intake manifold, valve covers, etc. Again, consult your shop manual for the proper installation procedure and torque specifications for each component.
4. Final Steps:
* Refill Fluids: Refill the engine coolant, engine oil, and transmission fluid (if applicable).
* Prime Oil System: Prime the oil system and check for leaks.
* Start Engine: Start the engine and carefully check for leaks. Allow the engine to reach operating temperature and monitor for any leaks.
Disclaimer: This is a simplified overview. Improper installation can lead to severe engine damage. Consult a detailed shop manual specific to your vehicle and engine for complete and accurate instructions. If you're not experienced with this type of repair, hire a professional mechanic. The cost of a professional repair is far less than the cost of a catastrophic engine failure due to improper head gasket installation.
