[Jim-Bob]

Camshaft theory is a fairly extensive subject to get into, but the basics are: Lobe separation, Lift and duration. Now lift is how far above the base circle the cam lobe's peak is. I (and the base circle is the portion of the lobe that the lifter is on when the valve is closed) It affects how far off the valve seat the valve will go at peak lift. Peak valve lift is in turn affected by the rocker arm ratio. If you had .500 lobe lift with a 1:1 rocker ratio, the valve would lift .500 off the seat. if you had a 1:1.6 rocker ratio ( you do), it would be .800 valve lift. (note that these numbers are for illustration only as only radical race engines have that much lift!). Duration is the amount of degrees of crank rotation that the valve is off the seat. This can be measured as gross duration or duration at 0.050 lift ( meaning from where the lobe is 0.050 off the base circle to where it closes to that figure). Lobe separation angle (LSA) is the included angle between the peak of the exhaust lobe and the intake lobe. This affects overlap, which is the number of degrees that both valves are open at the same time. Wider LSA figures do not fill the cylinder as well at higher RPMs, but do build more cylinder pressure lower down in the RPM range. Thus, a wide LSA cam will have more low end torque than a narrow LSA cam, all other things being equal. This affects the dynamic compression of the engine which is different than the static compression ratio of the engine. While static compression ratio is important, it is the peak cylinder pressure that makes all the difference. Remember that the compression ratio is the measurement of the volume of the cylinder and combustion chamber at bottom dead center (BDC) compared to the volume at top dead center (TDC). How much pressure is actually trapped in the cylinder is a function of the camshaft and cylinder head port design and will determine how the vehicle drives. This is also why many modern cars with double overhead cam engines can vary the lobe separation angle via the use of a solenoid valve that changes the relative positions of the two cams. Some also have two different cam lobes that switch at a given RPM as well (Honda VTEC being the best known of these) to extend the power curve. However, your 1962 engine design is not that sophisticated and you will have to choose carefully the cam that best suits your needs and matches the rest of the components of the vehicle.

Try looking at Comp Cams online catalog ( http://www.compcams.com/ )for some ideas as to what is available. They should also have a good section on their site about theory as well. I used one of their Xtreme Energy cams (XE262) in my Chevy 355 and it made a huge difference in both FE and acceleration. To chose that cam I used a dyno sim program and entered a lot of parameters (including flow bench data I found for my heads online) to get the most accurate match possible and maximize torque. A similar program is available to download for free off their site, but it probably only deals with their cams. Look at their truck cams, especially the smaller ones to get an idea of what is available to improve mileage and driveability. Your particular engine should be equipped with a roller cam, so all you need is the cam and a timing set. The old lifters can be reused. If it were a flat tappet cam then the lifters would need to be replaced at the same time.