If the cam happens to drop in dead-on spec, there is zero to be gained. Most of the time (95%) they drop in +-2*. Nothing you'll ever notice on the street or, frankly, at the strip with most combos. But there are those times when something is really out of whack that you'll be glad you caught before you fire the motor up the first time. I've found a timing chain with the dot on the top gear off by ONE FULL TOOTH. And I've also found some cams that call for an intake centerline that is NOT already ground into the cam (usually shows retarded from cam card spec by about 4-5* when that's the case).
So, the vast majority of times it's not going to be a problem. But do you want to take the chance? It doesn't take long to check at least the #1 intake lobe centerline (point of max lift in most cases) against the cam card spec. Maybe an hour to do it, being reasonably careful (assuming the motor is on a stand with the heads off already).
Couple years ago I figured out a frustrating problem with a freinds motor that pulled like a beast down low but just didn't have the Wheaties up top. 2 YEARS of trying different bolt-on parts couldn't fix it. A quick degree operation on the cam showed the ICL was off by about 4* from spec AND THE LIFT WAS NOWHERE CLOSE TO CAM SPEC. Whoever built the motor simply shoved in the wrong cam- simple as that. We installed the RIGHT cam and the car dropped 8 TENTHS on it's next run at the strip. You can imagine the level of frustration that existed prior to finding out about this! It can happen to you, too.
