Vintage/SCCA Regional/autocross spec race head, with unleaded seat conversion. Keith Calver has performed hours and hours of testing to perfect his own range of modified cylinder heads. Years of development have resulted in what is possibly the best over-the-counter race head in this price range.

• Inlet valves: 35.7mm(1.401") diameter plasma-nitrided EN214N stainless steel
• Exhaust valves: 29.5mm(1.16") diameter plasma-nitrided EN214N stainless steel
• Valve Guides: Magnesium bronze
• Valve Springs: Nominal 240 lb. at 0.500" valve lift.
• Stem Seals: Latest 'top-hat' design with tensioner springs. Note this head is also used on hot road engines, so it is supplied with 8 valve seals.  For race use, we recommend removal of the exhaust seals for better lubrication of the valves at high rpm.
• Chamber Volume: Nominal 21cc.
• Modifications have been made to deliver real world HP. This is done not by giving more "peak flow" than others, but with better mid-lift flow throughout the curve and superior exhaust port performance. Performance equivalent to or exceeding Longman GT14.
• Sport head features:
  • Shimming springs to precise installed heights
  • A+ valve seals
  • 3 surfaces of casting machined
  • Stud holes countersunk
  • All holes cleaned
  • All threads chased
  Rust-proofing on machined surfaces
• 21cc chambers
• 4 angle inlet seat, 3 angle exhaust seat

Modifications have been made to deliver real world HP. This is done not by giving more "peak flow" than others, but with better mid-lift flow throughout the curve and superior exhaust port performance. Performance equivalent to or exceeding Longman GT14. Unleaded valve seat (4) conversion.