Flathead Power® cylinder heads for Flathead Power KN-Series 3 5/8" bore engines, can also be used as replacement heads for stock and modified 1940–'47, 61" and 74" OHV engines. Heads are cast from high quality engineering grade grey iron, and have a stock-look black powdercoat finish. The larger 1.940" diameter intake valve and a stock 1.750" diameter exhaust valve, allows them to handle the larger displacement of the KN93 engines, but works as a high performance upgrade for 61" and 74" engines as well. To maximize compatibility, these heads are machined with a counterbore for a fire ring on the top of the stock 61" cylinder, and are drilled with the stock bolt pattern. However, head bolt holes are 7/16" -20 thread and will not work with stock 7/16" - 16 thread head bolts.
Fits KN-Series engines, 1940–'47 OHV big twins and 1936–'39 with a manifold upgrade
Features and Benefits
- Made of engineering-grade grey iron–better heat dissipation, less sound transfer
- Durable stock-look black powdercoat finish
- Counter bore for 61" cylinder fire ring
- Set up for o-ring manifold or late style port plumber fittings
- 1.940" intake and 1.750" exhaust valve
- Valve springs allow cams with up to .480" lift
- Compatible with stock or S&S valve cover "tins"
Options: Assembled or Unassembled with guides installed for use with S&S "tins" (valves ground) or Guides not installed for use with stock "tins" (valves not ground). 14mm or 18mm spark plug hole
Note:Cylinder heads for KN-Series engine or stock knucklehead are set up for Flathead Power® tins. Valve guides are installed. Guides cannot be installed for heads set up for stock tins.
