The VN style asymmetric port Yella Terra alloy head is the first choice among serious engine builders seeking maximum power from any Holden V8 engine. The intake & exhaust port design has been significantly improved “as cast” and a greater amount of material is retained between water jackets to allow more radical porting by cylinder head specialists. Great attention has been given to straightening the path from manifold to valve including relocating the exhaust valve further away from the intake and straightening the exhaust port exit. Subtle improvements into the basic design such as careful blending of the metal around the valve guides contribute to the excellent “as cast” flow figures with over 520 horsepower potential out of the box, with 2.02” size intake valves. The chambers can accommodate massive 2.08” intake valves and are fitted with quality valve seat inserts, compatible with unleaded and LPG fuels. The enormous power potential of YellaTerra VN style alloy heads can be adapted to pre injection 308 Holden engines when used in conjunction with VN style intake manifolds or injection, VN style flat tappet or roller camshafts and VN style exhaust headers. The Ultimate power fix for ALL Holden V8's and offer the added advantage of a 50% weight reduction over cast iron factory heads. NOTE: 'Bare Heads' have been finished machined with brass guides fitted not reamed, material left on the joint face for final milling. NOTE: These heads require Yella Terra shaft type Platinum roller rockers (YT 6313) NOTE: Inlet ports still suit injected and non-injected manifolds. Features: Suits: Holden 5.0L (304,308,355,383) Material: AS 601, 356 -T6 heat treated aluminium Min Hardness: 88HB Weight: Bare 10.8kg - Assembled 12.7kg CC Vol.: 59cc w/ 2.0mm extra joint face material - 44cc with face machined to std GM thickness Deck Thickness: .625” Inlet Port Vol: 168cc w/o injector notches Inlet Port Dimensions (hxw):52mm x 31mm Exhaust Port Dimensions (hxw):35.5mm x 35mm Inlet Valve Size: 2.020”min - Insert Size 2.200” x .375” Exhaust Valve Size: 1.600”min - Insert Size 1.750” x .375” Spring Pockets: 1.50”dia min - Material Thickness .420” Installed Height: 1.760” w/ std length valves Valve positions: Inlet valve: std position - Exhaust valve: moved 2.0mm away from inlet - Exhaust port exit: moved 2.0mm opposite Spark Plugs: Machined to accept tapered seat or washer seat spark plugs
The VN style asymmetric port Yella Terra alloy head is the first choice among serious engine builders seeking maximum power from any Holden V8 engine. The intake & exhaust port design has been significantly improved “as cast” and a greater amount of material is retained between water jackets to allow more radical porting by cylinder head specialists. Great attention has been given to straightening the path from manifold to valve including relocating the exhaust valve further away from the intake and straightening the exhaust port exit. Subtle improvements into the basic design such as careful blending of the metal around the valve guides contribute to the excellent “as cast” flow figures with over 520 horsepower potential out of the box, with 2.02” size intake valves. The chambers can accommodate massive 2.08” intake valves and are fitted with quality valve seat inserts, compatible with unleaded and LPG fuels. The enormous power potential of YellaTerra VN style alloy heads can be adapted to pre injection 308 Holden engines when used in conjunction with VN style intake manifolds or injection, VN style flat tappet or roller camshafts and VN style exhaust headers. The Ultimate power fix for ALL Holden V8's and offer the added advantage of a 50% weight reduction over cast iron factory heads. NOTE: 'Bare Heads' have been finished machined with brass guides fitted not reamed, material left on the joint face for final milling. NOTE: These heads require Yella Terra shaft type Platinum roller rockers (YT 6313) NOTE: Inlet ports still suit injected and non-injected manifolds. Features: Suits: Holden 5.0L (304,308,355,383) Material: AS 601, 356 -T6 heat treated aluminium Min Hardness: 88HB Weight: Bare 10.8kg - Assembled 12.7kg CC Vol.: 59cc w/ 2.0mm extra joint face material - 44cc with face machined to std GM thickness Deck Thickness: .625” Inlet Port Vol: 168cc w/o injector notches Inlet Port Dimensions (hxw):52mm x 31mm Exhaust Port Dimensions (hxw):35.5mm x 35mm Inlet Valve Size: 2.020”min - Insert Size 2.200” x .375” Exhaust Valve Size: 1.600”min - Insert Size 1.750” x .375” Spring Pockets: 1.50”dia min - Material Thickness .420” Installed Height: 1.760” w/ std length valves Valve positions: Inlet valve: std position - Exhaust valve: moved 2.0mm away from inlet - Exhaust port exit: moved 2.0mm opposite Spark Plugs: Machined to accept tapered seat or washer seat spark plugs

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