We always had great luck running the Crower 267/271 cam in the B motors with Rhoads lifters. At 5000' we were gaining a bunch of torque even in the big heavy cars. That cam in a Blues Brother Monaco with a 440 and it would lay rubber easily. I might even consider going up to the 271/284 especially with the Rhoads VMax lifters. You get the longer duration and higher lift and good vacuum at idle. I can imagine at 700' it should be a much more spirited ride.