Above from Cam Calculator... 1st and 3rd columns are factory cam.

I'm gonna' take a chance, I've done my homework!

I still have my factory cam in '99 5.9 magnum Durango. I put the specs in a cam calculator and it really didn't look too bad. If I advanced it 12 degrees it looked a lot like a cam in bewteen Comps' 254 and 264 cams.
So...., I already have the 4 degree timing set, if I advance the cam gear 1 tooth that's +15.65 (720 crank degrees / 46 teeth), then back up 4 crank degrees with the timing set (-4 = 11.65).

Is it possible they tried to give us a decent cam, and the emissions guys just had them spin it backwards until it came in spec?

I'm also thinking since 254/264 are higher cams with no valve/piston concerns (just springs), I'm good for any potential clearance problems (the stocker will still be at only the stock .410).

Did I miss something?

 

I got it in/done.
Using the Cloyes +=- set....
I was advanced 4
Set back to -4, then advanced 1 tooth.
Intake Centerline came out to 106, so now 3.5 advanced!

Waiting for oil pump, etc to start up.

 

In case anyone is following along...

I'm about 300 miles out, and the takeoff - say 0-30 mph shows no change.

But, I swear I think the 60mph range is using less fuel - just a bit - as my routine local runs seem to be a mpg higher at speed.
Almost makes sense if I moved the 'power band' lower (say a bit towards the 2K or so for 60mph) that maybe I gained a bit of efficiency (torque) in a lower RPM. I would gladly give up 5 HP on the top for 1 mpg in my interstate range.

 

It's not gonna be definitive, but if you find a download of desktop dyno out there and plug in everything for the motor and cam it should give you a decent idea of where the power moved.

 

If that's the one I'm thinking of, I tried to try it before I did it.
It wanted sooo much detail (head volume, for instance, that I just wasted a bunch of time researching data that wasn't gonna' change.