| Technical FAQs |
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Which cylinder heads do I have and what are the component specs for the valves and springs? |
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All the heads we make have cast-in letters and codes under the valve cover. It is important to note that World ... |
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Which pushrods should I use? |
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We advise that you acquire an adjustable checking pushrod to get an exact spec. Variables such as rocker ratio ... |
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Which spark plugs do I need? |
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World head combinations and crate engines (BBC, SBC, SBF & Mopar) use either Accel 276* (iron heads) or 416 (al... |
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Why do I have distributor trouble or engine misfiring if you ran this engine on a dyno |
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All our crate engines are dyno tested - however, the only time 12 volt battery power is in effect is actually s... |
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I have a rear main seal leak, why did you ship the engine to me that way? |
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The truth is, we didn't. As we complete the assembly of an engine, we add a leak detection dye to the oil. Afte... |
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Why do aluminum heads make more power? |
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They really don’t make more power-by themselves. Aluminum can dissipate heat better than cast iron heads, all... |
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How can I determine valve lift if I change rocker arm ratio? |
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Using the advertised valve lift of your cam, divide that figure by the current rocker ratio. This figure is you... |
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What does “Racer Special” porting mean? |
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These procedures consist of matching the port opening to the required gasket by slightly hand grinding the port... |
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When should I be concerned about piston to valve clearance? |
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As an engine builder, you should check this clearance anytime a parts or machining change is made which may aff... |
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What do the terms “internal” and “external” balance mean? |
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The procedure for internal balancing begins by measuring the weights of the piston, wrist pin, rings, rod and r... |
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What is the best compression ratio for street operation with pump gas? |
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The engines we build range from 9.5:1 to 11.6:1 for the 91 octane pump gas Street engines. Our Race series engi... |
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How much can I mill my heads? |
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Flat milling is at discretion of the Engine Builder. The intake seat is the limit of a flat mill, but deck thic... |
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