Camshaft for mustang?

Question

Im building up a 82 mustang GT. Im building up a nice bored over 302. Ive been checking out camshafts. Ive noticed that some have the same duration and lift for intake and exhaust. Other camshafts have more lift and duration on the exhaust then the intake side. Im confused Im purchasing some heads with 2.02 intake and 1.60 exhaust valves. I just dont understand why some cam's are the same intake and exhaust but other's are not. Can some one exlain why there like that?

Answer 1

There are several #'s that you'll see with camshafts.  The first is advertised duration, the second is the @ 50 duration.  The third is lift, and finally the degrees of separation.  Basically the compression and valve size/head flow will affect your selection.  The split duration cams work best with low compression engines (below 9.5 to 1).  They tend to deliver a broader power curve across the rpm range.   For higher compression engines the cams that have the same lift/dur values work better.  That brings up the degrees of separation.  For naturally aspirated engines a cam that has some overlap (where the intake and exhaust valves have a point where they are both open).  This promotes a scavenging effect in higher rpms.  Cams with little or no overlap work well with forced induction and nitrous.  Then there is lift/duration, there is a proportional relationship between those #'s and horsepower and torque.  Most important, match the cam to the rest of the motors parts and you'll be happy with the results.  If you mismatch parts, the motors performance will be adversely effected.  Good luck.