Always degree a cam when installing it. It is of the utmost importance to firstly, know where TDC is EXACTLY, and second, to have that cam set up from the corrected TDC.
Aftermarket parts are notorious for pushing tolerance limits. Example....a new harmonic balancer on my 79 GT's 360....the balancer was out 2 degrees in the factory markings. I slipped an old Mope balancer on and re-ran the numbers.....the factory balancer was dead-on. I ran the numbers again using a 360 balancer a buddy had.....again the factory unit is spot on.
Back goes the new replacement unit.....run the numbers....still 2 degrees out. The simple fix is a timing tape around the new balancer.
Now....imagine if you just dropeed a cam into this without checking. We already have 2 degrees misalignment with one part....what if the cam is out by a degree or two as well? Then you have the possibility of being up to 4 degrees off of where the manufacturer wants his cam to run at. Then there are the ignition timing issues that would arise as well.
Comp Cams makes a nice kit for under a buck and a half, that allows you to set virtually any engine.
As UCUDANT pointed out....degreeing a cam isn't an overly difficult job, just tedious and exacting. But do it once or twice and you'll get a firm understanding of why it must be done.
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