Cannonball Aluminum Cylinder Head set “knucklehead”
There heads are a precise reproduction of the stock Knucklehead cylinder heads, cast from aluminum! Besides the significant weight savings of approx. 4 kg per head they dissipate heat much better than their cast iron counterparts. They are manufactured after 1940-1947 heads with large intake ports. The valve seats are pre-installed, but unmachined and sized for stock intake and exhaust valves. They are hardened for the use of today’s unleaded fuels. Steel inserts for the head bolts feature factory threads. The heads show all the small details like cast-in number tags and foundry markings, so they make for excellent stock replacements or for building a performance engine with factory look when you camouflage them with black paint.
fits OHV models 1936-1947
cast aluminum, bare
nominal bore: 3-7/16 ”
exhaust flanges G: Knucklehead
head bolt pattern: Knucklehead
intake manifold flanges: Knucklehead plumber type (1940-1947)
oil supply: external
plug threads: 1 x M18 x 1.5 x 12.7 mm
replaces OEM 16700-40, and 16697-40
gross weight: 8.59 kg
Installation of Valve Guides and Tins
Unlike cast iron heads, Knucklehead aluminum heads need to be pre-heated and the valve guides be cooled for proper installation. Important: temperature for the heads must not exceed heat resistance of the valve tin sealant.