501 Series Performance Type 1 Head Bare No seats AMC 5:1 with the 70

5:1 with the 70

They have a 0 offset with extramaterial under the top for thevalve pocket

Compression:9

1 Piston Set

Centrifugal advance Distributor

501 Series Performance Type 1 Head Bare No seats AMC 5:1 with the 70AA 501 Series Casting, It is set up to build the performance Head of your needs. It Comes bare with a 12mm plug hole, and with out Seats or Guides. Giving you the the ability to build any possible combo Street Drag head you want. Seat Pockets start with the Stock 35. 5x32 valve size Configuration and can be machined up to the 44x37. 5mm The 501 Series Castings come STD with: Increasedmaterialat the intakesurfacegivingyou theabilityto make much bigger