The BB-1 rectangular port head has a 280 cc intake port and a 119 cc combustion chamber, but may be angle milled to 108 cc or angle machined to 98 cc. The BB-1 is designed for a 396 to 502 engine with a
flat tappet or hydraulic cam. Most marine applications use this head for torque and throttle response.

The BB-1, out of the box, may have spring pockets cut to 1.625, but no larger or deeper. This head accepts all standard parts including intake manifold, pistons, headers, pushrods, and valve covers. The exhaust ports are raised .600 higher than stock.

The BB-1 also comes completely CNC ported by M2 Race Systems. The 305 cc intake port flows over 370 cfm and has maximum port velocity. Price per head.