Product successfully added to your shopping cart
Translation missing: en.products.wishlist.added_to_wishlist
Qty:
There are item(s) in your cart
- 255cc Intake, 95cc Exhaust & 69cc Chambers
- Virgin A356 Aluminum Castings
- 6 Bolt Head Casting with Extra Strength Decks
- Advanced 11° Valve Angle for Maximum Flow & PTV Clearance
- 2.165” Intake Valve 21-4N Alloy & 1.60” Exhaust Valve 23-8N Super Alloy
- 0.210" Intake Free Drop & 0.250" Exhaust Free Drop
- 23-8N Alloy has the same high temp characteristics of “Inconel” w/o the brittleness
- Available Complete w/ Chromoly Retainers, Ti Retainers, or Bare w/ Valves
- Billet Rocker Arm Stands Included - Compatible w/ OEM LS3 Rocker Arms
- Compatible w/ 4 Bolt OEM Engine Blocks - 4.000" Minimum Bore Required
0.660" Spring Specs:
- 145# @ 1.800"
- 400# @ 1.130"
- CB @ 1.070"
0.700" Spring Specs:
- 170# @ 1.800"
- 450# @ 1.115"
- CB @ 1.000"
| Valve Lift | Intake | Exhaust |
| 0.200" | 138 | 111 |
| 0.300" | 209 | 150 |
| 0.400" | 263 | 178 |
| 0.500" | 321 | 196 |
| 0.600" | 324 | 213 |
| 0.700" | 342 | 222 |
Head Flow Data @ 28inHg, 4.125" Bore, Intake w/ Radius, Exhaust w/o Pipe
It MUST be noted that comparing flow data across different flow benches and cylinder heads is NOT the correct way to measure a cylinder head's performance. A flow bench measures static air flow while the engine's valve is at a stationary position. In the real world, the valve nor the air in the cylinder head's runner is ever stationary. The air/fuel mixture is constantly being pushed, pulled & pulsed by the pistons & other cylinder's valve events. A well performing cylinder head must be able to respond to the valve opening and efficiently deliver the air/fuel mixture that the engine is requiring, while also keeping turbulence to a minimum. This is where the Smeding 11° design is unbeatable. On the dyno these heads will out perform other manufacture's 12° designs, even though they advertise higher flow numbers. Below is a dyno comparison of our 11° 260cc CNC cylinder heads vs a competitors 12° CNC 260cc cylinder heads. The test engine was a mild 11.0:1 441" LS engine with our 245/256 Rectangle Port R4 Stroker camshaft. Both dyno pulls were done the same day, with both tunes optimized for each combination. As you can see the 11° Smeding heads outperformed the 12° competitor's heads across the entire curve.
