Remove all paint from the gasket mating surfaces prior to assembly. Use acetone or lacquer thinner if available. A razor blade or gasket scraper can also be used but care must be taken to not damage the surfaces. Once the gasket surfaces are clear, it is a good idea to use compressed air and blow out any debris from both the water and exhaust passages. Some manifold manufacturing processes can leave behind metal debris and particles.
With the old manifolds removed, inspect and clean as necessary the mating surfaces on your engine head(s). Ensure there is no debris in the exhaust ports. Now may also be a good time to inspect the exhaust ports and valves to make sure they are in good shape and do not show any signs of rust or corrosion. If your previous exhaust parts were failing and allowing water into the exhaust passages, your engine may need repairs.
Bolts and Hardware
In many cases you can reuse your previous bolts, studs, and nuts, if they’re still in good condition. You should replace lock washers where appropriate. Refer to the exhaust manifold bolt guide if you need new hardware.
Unless otherwise stated in your product or manufacturer manual, gaskets should be installed dry without any gasket sealer, silicone, or compound. When installing riser and elbow gaskets, make sure they are in the same orientation as before (for gaskets that are not symmetrical).
Refer to your manual for proper bolt torque. If not available, use this chart:
Plugs and Fittings
When installing pipe fittings or pipe plugs care must be taken to avoid over-tightening. Most pipe plugs and fittings are tapered and an overly-tight pipe plug or fitting can crack the casting. Do not use thread sealants which contain Teflon. Do not try to screw the plugs in flush with the casting; they only need to be snug.