Editing Hotrodding the BBC 454 engine

==Intro== ==Specific tips== 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. ==Power below 3000 RPM:== 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. 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. 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. 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. ==Static CR== *[http://www.wheelspin.net/calc/calc2.html SCR] ==Dynamic CR== *[http://www.wallaceracing.com/dynamic-cr.php Wallace Racing DCR calculator] *[http://www.empirenet.com/pkelley2/DynamicCR.html Kelly DCR calculator] *[http://www.uempistons.com/calc.php?action=comp2 KB/Silvolite DCR calculator] *[http://www.rbracing-rsr.com/comprAdvHD.htm RSR DCR calculator] {{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. {{Note1}}If the intake valve closing (IVC) point isn't known, it can be calculated: # Divide the intake duration by 2 # Add the results to the lobe separation angle (LSA) # Subtract any ground-in advance # Subtract 180 This result does not need to have any amount added to the IVC point, like the KB calculator calls for. ==References== [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. <br><br> [[Category:Engine]] [[Category:Undeveloped articles]] [[Category:GM]] [[Category:Undeveloped Engine articles]]

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