My Turn for a Cam question - 318 Build

As above....... Keep in mind with the 5200' altitude, you're gonna lose a lot of DCR. Going to the 250 at 5200' won't even equalize the DCR loss at 5200' versus the 256 at sea level. So the Comp calculator numbers are going to be overly high, and if you want low end torque, it might be best to keep to the smaller cam.

Or, put in some more cam advance, maybe another 3-4 degrees. Or consider a cam with a narrower LSA, with the 250-ish durations to close the intake even sooner. (As suggested.) The altitude is going to be your biggest headache for cam selection and maintaining low end torque IMHO; your DCR's will be down below 7 with the altitude, and cranking pressures will be close to that of a stock /6 at sea level. (Assuming the .028" head gaskets.)

I would very strongly consider milling the head about .040-045" each to get the chambers down to around 58 cc's. That will push the DCR up around 7.4 and get the cranking pressures up around 145 psi with the XE250 cam, and around 7.25 and 141 psi with the XE256 cam. Good for the torque you are seeking....