| Re: some Cam questions (beginner) For starters welcome to the web site youll see there are many very knolegeable people here that are always more than willing to help. Also,I can understand your english prety well and my spelling sucks pretty bad too so no worries there. Well as youve probably seen cam's are a fairly complecated matter (yes you can just call it a cam its commonly understood cam refers to a camshaft). Now because i dont know what you already know about cams let me just throw a whole bunch of basic cam theory at you. Theres several specs to concern your self with primarily lift and duration but also things like degrees of lobe seperation. First the basic theory of cams is the more lift you have the more power you will make and the longer the duration the higher RPM your peek horsepower will occure at. Breaking that down even further the more lif you can get the more power you will make across the RPM range and long duration cams will make more high RPM horsepower but shorter dutation cams will make more low end torque. Not so bad so far right? Now this is really overly simplified but gives you a good idea of what it basically means. Now degrees of lobe seperation is kind of complex as its hard to really say its effects without taking into account the other specs. What it means is its the angle in degrees between the cams intake lobe peek and the cams exhaust lobes peek. What does this mean to you without getting real crazy into the science of its actual effect? A greater degree of lobe seperation will generally improve high end hp and give a wider power band where as a cam with less degrees of seperation will have increased low end torque and a narrow powerband. Other things you were asking about is the 1.5 or 1.6. This is the ratio of the rocker arms the 1.5 means 1 inch of lift on the cam will make the valve lift 1.5 inches with 1.5 ratio rocker arms or with 1.6 ratio rocker arms 1 inch of cam lift will be 1.6 inches of valve lift. Dosnt seem like much but it can make a bit of a difference in performance especially on cams with low lifts. Now the other number you were asking about the .050. There are 2 ways the duration specs are measured "advertised" and at ".050". "Advertised duration" can be measured from where ever the manufacture defines. However each manufacture could define the point they measure from differently. This means theres no way to really compare cams between different manufacturers. So many years ago an industry standard was set in place to measure the duration at .050 inches lift. That way all the duration measurements will be made from the same point on the cam and allows for the customer to be able to compare camshafts. Now your question about swapping cams from other motors you can do that but the cam your looking at from the 1987 305 will not perform as well as the duration is less and so is the valve lift. The current cam you have isnt too bad for a street car and concidering the amount of money and work it will take to change it ide say you would be better off changing to 1.6 ratio rockers (stock rocker arms are 1.5). This will improve valve lift giving you a little more power across the RPM range. Now if you did want to change the cam there are alot of nice aftermarket cams and a few talored specifically to TPI motors that will give a nice boost in performance more so than just adding 1.6 ratio rockers.
Last edited by Rolling Thunder; 07-11-2009 at 01:42 AM.
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