Our fully CNC ported Promaxx heads are a very capable set of cylinder heads for the price. We typically produce around 650HP on our stroker big block engines with these heads.

Features

• Intake runner volume - 240cc
• Exhaust runner volume - 95cc
• Intake valve diameter - 2.19"
• Exhaust valve diameter - 1.81"
• Valve stem diameter - 11/32"
• Valve guide - Manganese bronze
• Valve spring diameter -
• Valve spring max lift - .650 lift
• Rockers - Standard
• Valve angle - 18 degree
• Includes spring with titanium retainers
• Valve spring seat pressure 145#
• Valve spring open pressure 400# @ .600 lift