
Americas favorite high-performance cast iron small block cylinder head offers big power and bigger value.
The Vortec cylinder heads fast burn combustion chamber and high velocity ports combine to produce big horsepower out of the box.
The Vortec head can be mildly ported for additional performance and can be milled up to .040"for increased compression ratio.
The Vortec head uses 1.94" intake valves and 1.50" exhaust valves to compliment the high velocity port design.
The Vortec head out flows the Bow tie head out of the box and is a 20 to 40 horsepower bolt on increase over earlier cast iron small block heads.
- Completely assembled with 1.940"/1.500" valves
- Uses bare head 12691727
- 62cc combustion chamber
- Straight spark plugs
- No heat risers
- Requires Vortec-specific intake manifold
- Camshafts with more than .475" lift require machining valve guide bosses and checking valve seal to valve spring retainer clearance
- Can be machined for 2.020"/1.600" valves
- Rocker arm studs can be pinned or drilled and tapped to 3/8"
- Valve spring seat diameter is 1.280"
- Casting number 10239906 or 12558062