i had got these heads on a crate motor i have. i had a problem with the springs. the springs are just too weak. i broke a spring and bent one of the valves. the heads only have 300 miles on them if that much.

they are complete minus one spring and one valve.

350 shipped. they got to go so let me know guys.

GM Performance Parts L31 Vortec Cylinder Heads. The best out-of-the-box head for the money. Excellent flow produces broad torque and killer power. Stock springs are good up to 0.450" lift. Requires special intake manifold to fit the Vortec bolt pattern. Price is per head.

Cast Iron L31 Vortec SB Chevrolet Cylinder Head Specifications:

Intake Valve Diameter (in.):1.940Exhaust Valve Diameter (in):1.500Valves Included:YesValve Seat Material:SteelValve Seat Finish: Quantity:NullCylinder Head Material:Cast IronCylinder Head Finish:NaturalAssembled or Bare:AssembledCNC Ported:NoIntake Runner Volume (cc):170ccExhaust Runner Volume (cc): Combustion Chamber Volume (cc):64cc

 

these are pretty much the same as the 906 heads arent they ? just that the 906 heads are crate motor heads ?

 

honestly i am not sure!