How Many Types of Vortec Heads are Offered?
• GM L-31 Vortec (Cast Iron) • GMPP ’small port’ Vortec Bowtie (Cast Iron) • GMPP ‘large port’ Vortec Bowtie (Cast Iron) • GMPP ‘Fast Burn’ (Aluminum) • Edelbrock E-Tec 170 (Aluminum) 170cc intake runner • Edelbrock E-Tec 200 (Aluminum) 200 cc intake runner • Dart OE Vortec replacement head 165cc intake runner • RHS Vortec (available with either 1.940/1.500 or 2.02/1.600 valves) • EQ “Lightning” Vortec Style Cylinder Heads (Cast Iron) On the non-bow tie L31 Vortec heads, the ports are larger than the older cast steel heads, so they outflow the older heads. The Vortec heads are a little bit lighter than the older heads and have a “kidney” or “heart” shaped combustion chamber that is more efficient than the double hump chamber. The L31 Vortec comes in two different casting numbers, 10239906 (#906) or 12558062 (#062). Originally, the stock #906 casting head was available in two versions. One version had an Inconel exhaust seat with single angle valve grind and was available on 1 ton truck
