| Q |
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Why are the heads called 3V heads? |
| Ans |
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The heads were given the name 3V, as they have the airflow potential of the 4V head with ports the size of a 2V head. So with the airflow of a 4V and the airspeed of a 2V we thought the title 3V fitted well.
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| Q |
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What spark plug type do the heads take? |
| Ans |
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Our heads take a ¾ inch reach 14x1.25MM thread, flat seat type spark plug. A good starting point is the NGK BCP6ES or equivalent style plug.
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| Q |
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How many CCs are the combustion chambers? |
| Ans |
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Our chambers are usually around the 66-67cc range. If a smaller chamber volume is required the heads can be ordered to suit individual requirements, and will be machined free of charge to the required chamber volume.
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| Q |
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What valve sizes do the heads come machined to suit? |
| Ans |
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All our cylinder heads come machined to suit a 1.650" Exhaust valve. Our 3V 185cc head has a 2.070" Intake valve. The 3V 225cc takes a 2.150" Intake valve and the 3V 250cc comes machined to suit 2.190" intake valves. Our 2V head has a 2.070" intake valve and finally the 4V head comes with a 2.190" intake.
We will however machine the heads to suit your own valve sizes if you wish at no extra charge.
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| Q |
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What type of headers do the heads take? |
| Ans |
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Our 3V 225cc & 250cc cylinder heads are designed to work with 4V headers. Although 2V headers will bolt up, they will require port matching for a proper fit. Our 3V185cc heads, and our 2V and 4V heads all come with our "Uni" exhaust port which allows the use of either 2V or 4V headers.
Our 3V 225cc & 250cc exhaust port also has a .420" raised exhaust port location. On the engine at 45 degrees this will move the headers up .210" and outwards .210". To compensate for this, all heads now come with the exhaust flange machined on a 5/8 degree angle, leaning the exhaust face in towards the bottom, to offset the effect of the raised exhaust port.
All heads can be specially ordered, with either the raised ex port or with the standard height ex port height at no extra charge.
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| Q |
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Do the heads have all the standard accessory bolt holes on the ends? |
| Ans |
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Our heads feature all standard Cleveland accessory mounting holes, and as of Nov 2005 will also feature all factory Windsor accessory mounting holes as well, making Clevor - Boss conversions easier than ever before.
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| Q |
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How tall are the 3V manifolds? |
| Ans |
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Our 3V manifolds to suit a 9.2" Cleveland block are 7.200" tall whilst 3V manifolds to suit a 9.5" deck Windsor height, are 7.500".
Our 8.200" 302W manifold is 6.375" tall.
All manifolds can be machined down by -.875" for extra hood clearance at no extra charge.
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| Q |
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Will the heads take standard head bolts? |
| Ans |
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Yes our 2V, 4V and 3V 185cc cylinder heads all come with standard height bolt pads. Our 3V 225cc & 250cc heads will need a .500" longer head bolt on the exhaust side only. However a standard Cleveland stud kit can be used with our 3V 225cc & 250cc heads, by not winding the stud all the way into its head bolt hole. This is safe to do with a stud, as the studs have far more thread engagement in the block than a head bolt does, so winding them out a few turns still results in them having equal or more thread engagement than a bolt would have.
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