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course on cam basics


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theres a BUNCH of factors that must be looked at...when matching components....

 

http://victorylibrary.com/mopar/intake-tech-c.htm

 

http://victorylibrary.com/mopar/cam-tech.htm

 

http://www.rbracing-rsr.com/runnertorquecalc.html

 

http://headerdesign.com/extras/engine.asp#Intake_Manifolds

 

http://www.bgsoflex.com/intakeln.html

 

http://www.wallaceracing.com/runnertorquecalc.php

 

http://www.mercurycapri.com/technical/engine/intake/pt.html

 

 

 

the calculators above will allow you to match the engines intake port length and flow rates

 

heres some basic rules of thumb as they say

 

 

keep the EFFECTIVE durration of the cam matched to the compression ratio so that the DYNAMIC cpr stays in the 7.5:1-8.5:1 range and the overlap matches the chart below

these are the valve timeing overlap ranges that are most likely to work correctly

trucks/good mileage towing 10-35 degs overlap

daily driven low rpm performance 30-55degs overlap

hot street performance 50-75 degs overlap

oval track racing 70-95degs overlap

dragster/comp eliminator engines 90-115 degs overlap

 

but all engines will need the correct matching dcr for those overlap figures to correctly scavage the cylinders in the rpm ranges that apply to each engines use range.look carefully at this chart 30228b.gif

 

example

http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=114681&B1=Display+Card

 

here is a hot street cam that works great in many 383 camaros with at least 10.5 static cpr with 3.5-4.1 gears

now the timeing is intake opens 29.0 btdc, closes 71.0 abdc exhaust opens 77.0 bbdc, closes 31.0 atdc so if we add the 29 to the 31 we get the overlap duration of 60 degs of which makes this cam fall in the center of HOT STREET

 

youll RARELY benefit from a single plane carb intake with a cam that has less than about 230 degs durration at .050 lift, below that a dual plane carb intake works better most of the time

 

 

header primary tube size should not greatly exceed the exhaust port size

 

 

http://www.slowgt.com/Calc2.htm#Header

 

http://victorylibrary.com/mopar/otto-c.htm

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