Cams for 318's

Take a look at
Howards Cams Hydraulic Flat Tappet Camshafts - 255 int./261 exh. Advertised Duration
all three listings have the same .006 seat duration
The bottom listing for the chevy is similar to most chevy .842 profiles at that duration when sold for a MOPAR with 1.5 rockers
The middle listing is similar to the chevy profile but with 1.6 rockers I do not think this is a special for the larger Ford lifter
Now the top show shows the difference when you use a master made for the larger MOPAR/ AMC .904 lifter
.070 more lift and most likely much more area under the lift curve
Not touting Howard here- these three were conveniently on the same page for this discussion
You can find shelf Mopar cams at this duration from Lunati Voodoo, Bullet, Engle etc with various lobe centers (I think the DC/MP has been discontinued)
or you can go custom, like from Jim at Racer Brown (Herbert has none in their catalog but does have some oldy moldie customs they should still work well and the price is usually "right")
My favorite is Mike Jones custom Mopar lobe it is shorter seat to seat and larger at 200
your heads, compression, intake, exhaust and trans/ gears will make a big difference on what you end up choosing
don't but a chevy cam in your MOPAR- like the oldie but goodie 268 comp mentioned above
Here's how you tell- just compare the Mopar grind with their small block chevy grind- if they are the same PASS