The Original B1 head features raised ports that offer huge flow increases over cast iron head. The 2.300 inch intake valves and the 1.780 exhaust valves have been repositioned to the bore center-line for greater performance gain. The raised exhaust ports will accept a stock header flange. This head also features raised and angled spark plug locations for more complete combustion and deck thickness that provide extra strength. The head can be flat milled to 47 cc or angle milled to 37cc. Contact us for your specific application and pricing.