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| − | ==Intro==
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| − | ==Specific tips==
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| − | Replace peanut port heads on dish piston truck engines with oval port closed chamber heads for a quick and relatively cheap power increase. Smaller chamber heads like the c/n 215 could be used for better compression than the larger chambers found on c/n 049 or 781 heads.
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| − | ==Power below 3000 RPM:==
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| − | Larger intake ports are the wrong move entirely. In fact, peanut-ports with good valves but no porting, on a domed-piston 9.5:1 454, will do 446 HP with a street-friendly cam, headers and a decent intake.
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| − | Peanut ports heads on a 454 will typically give peak HP at 4900 RPM, with cams from 212 to 228 degrees intake duration at 0.050" lift.
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| − | Swapping to the large-oval (intake port) heads can help make power further up the rev range. Most of the '70s, '80s and early '90s pickups had around 7.9:1 compression with flat-top pistons and large "open" combustion chambers.
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| − | None of the "closed" chamber heads had hardened exhaust seats needed for unleaded gasoline, and these heads are coveted, plus the production numbers were far less than the peanut ports.
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| − | ==Static CR==
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| − | *[http://www.wheelspin.net/calc/calc2.html SCR]
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| − | ==Dynamic CR==
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| − | *[http://www.wallaceracing.com/dynamic-cr.php Wallace Racing DCR calculator]
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| − | *[http://www.empirenet.com/pkelley2/DynamicCR.html Kelly DCR calculator]
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| − | *[http://www.uempistons.com/calc.php?action=comp2 KB/Silvolite DCR calculator]
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| − | *[http://www.rbracing-rsr.com/comprAdvHD.htm RSR DCR calculator]
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| − | {{Note1}} Some dynamic compression rtatio calculators (like KBs) ask for an additional 15 degrees of duration be added to the IVC @ 0.050" lift point figure. This works OK on older, slower ramped cam lobes, but the faster lobe profiles may need to have 25 degrees or more added to be accurate.
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| − | {{Note1}}If the intake valve closing (IVC) point isn't known, it can be calculated:
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| − | # Divide the intake duration by 2
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| − | # Add the results to the lobe separation angle (LSA)
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| − | # Subtract any ground-in advance
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| − | # Subtract 180
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| − | This result does not need to have any amount added to the IVC point, like the KB calculator calls for.
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| − | ==References==
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| − | [http://www.carcraft.com/techarticles/ccrp_1010_cheap_big_block_chevy_engine_build/index.html Car Craft 454 build] baselined with peanut port heads, 446 hp at 4,900 rpm and 542 lb-ft at 3,600 rpm.
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| − | <br><br>
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| − | [[Category:Engine]]
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| − | [[Category:Undeveloped articles]]
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| − | [[Category:GM]]
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| − | [[Category:Undeveloped Engine articles]]
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