Indy's new 401-1 CNC cylinder heads are a work of art, featuring 300cc intake runners, that reportedly flow 390/282-cfm on the intake and exhaust respectively! Stock AMC "dog-leg" heads have roughly 166cc intake ports. With a 58cc combustion chamber, a flat-top piston will get you up over 14:1 compression. Indy o-ringed the heads, and fitted them with Manley 2.25/1.81 intake/exhaust valves. Indy built their heads so that they have six bolts per cylinder. The 401-1 is essentially a big-block cylinder head for a small-block, and at 300 cc, nearly perfect for a bracket racing engine in the 470 to 500ci range.