HONDA GX390 / PREDATOR 420 HEAD/ DUROMAX 420,440/ LIFAN 420 PORTED, BRONZE GUIDES, POLISHED. Does not include valves. NEW PERFORMANCE CYLINDER HEAD. Fits : Predator 420 / GX390 / duromax 420,440 / lifan 420 and more of this style. Brand new and heavily modified cylinder head for racing applications. Cylinder head design allows the intake charge to get supercharged during valve overlap with proper cam selection/design and this head is the best at this. This makes modified head such a great tuning option. And the best head to run on the GX390/ 420 / 440 / 460 +. This creates the quench effect which is tight areas between the piston and the head squeezing jets of air that create greater fuel mixture motion. This creates higher horse power levels with increased fuel efficiency. If you have to choose between quench and compression you want to choose quench. Thats because quench creates motion and pushes all the fuel and air to the middle of the chamber for a more controlled combustion. Radius shaped bowls to increase cylinder fill and velocity around the valve. Documented on the flow bench with smoke and refined shape produces a visible champagne glass flow travel path around valve perfectly filling the cylinder. This head comes with valve seats for 38mm intake and 34mm exhaust valve. Bronze guides installed and are reamed to size and then honed with a small ball hone to create a cross hatch to hold oil (completely optimized). Clearance and transition to spark plug is refined and shaped perfectly for better burn and more power. Spark plug position within the head is extremely important in creating power. Polished chamber has a dramatic effect called thermal reflectivity (this is the same effect a ceramic coating creates but to a less degree) thermal reflectivity helps minimize thermal losses. Harnessing the thermal energy even in small amounts adds up. I utilize every and all of these small gains to create big power. Multi angle valve job (5 angle seat cuts) improves flow in all rpm ranges extremely effective at improving flow in low lift… And thats the most important area to improve flow thru. Twice as important than high flow since the valve passes this area twice during the cams lobe profile. I have had spent a lot of time developing my seat design and set them all up the same every time.. I use calipers to measure the widths of the angles and have all the cutters to cut more angles then most other shops.. Truthfully before I did this myself I couldnt find anybody to do what I wanted to these seats.. I just wanted them right!! Thats one of the main reasons I started this work myself and for others. Bronze guides installed and reamed and honed to exacting tolerances. This keeps the valve much more stable at rpms and cooler valve temps. Allowing lower octane fuels to be used. Notice the trend of optimization towards head overall design. Guides bullet shaped prior to installation on lathe to shape that I found flows best on the flow bench. Ported intake and exhaust ports, my only stage, just done right!!! . These port designs are developed on my flow bench. THAT I ACTUALLY HAVE, OWN & USE DAILY! And I guarantee it will flow and perform as good as it looks. This head is truly a piece of performance art! Intake port has been polished or epoxy coated (optional but recommended) this will break down the boundary layer of air on the edge of the port walls this makes the port appear bigger than it is to the oncoming air this also helps keep the fuel atomized during its time in the port. Fuel in gas form is much more powerful than in liquid so keeping it atomized is key. Polished exhaust port to a mirror finish. Keeps carbon build up off the walls and lower the temp of the head.. Again the thermal reflectivity in action. These thermal reflectivity actions taken in this head make better use of the gas that goes they the engine. Out of all the gas you burn only 20% goes to propelling you down the road. The other 80% is lost to heat dissipation into the block and head. If we can improve that number even by 1-2% that equals HUGE increases in overall power. This head has cantered valve angle and a wedge shaped chamber optimal for flow and for increasing cam performance by increasing the way the exhaust driven , intake supercharging effect takes place… Watch my videos on the 5 th cycle to see how this effect is the key to Building horse power. This 5th cycle is the true tuning effect. When exhaust lengths and intake lengths are optimized you can dramatically alter wave length tuning. This head is the unlocking key. No head core is required to be sent.. This price includes the new Big block casting. This head is created by Pauls karts , Pauls karts channel can be found on you tube and offers build information and helpful facts about engine building. The contact information for my shop is also listed on all new videos put out this year.. Feel free to message me with question concerning fit of this product.. This head fits gx390, Predator 420, duromax 420,440, lifan 420 and more. Please allow 5-7 days for build time. All head are custom made to order. These heads can be custom tailored within the ports so let me know what carb your using or camshaft youre using I can make shuttle changes to fit your exact design. Thank you for your support. The item “460cc big block CYLINDER HEAD BIG VALVE, PORTED, BRONZE GUIDES, MULTI” is in sale since Tuesday, April 14, 2020. This item is in the category “eBay Motors\Parts & Accessories\Performance & Racing Parts\Kart Racing Parts\Other”. The seller is “pauzukauska_0″ and is located in Hyde Park, Massachusetts. This item can be shipped to United States, Canada, United Kingdom, Australia, Mexico, Germany, Japan, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Greece, Portugal, Cyprus, Slovenia, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Austria, Bahamas, Israel, New Zealand, Singapore, Switzerland, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Ecuador, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Peru, Pakistan, Paraguay, Reunion, Viet nam, Uruguay, Philippines, Ukraine.

• Modified Item: Yes
• Manufacturer Part Number: Does Not Apply
• Modification Description: Fully loaded with options, ported , 38/34 seats cut multi angle valve job (5) angle, bronze guides, polished, amazing ! Full racing head.
• Brand: Unbranded