Hard to say what's what there because as you said, too many variables. In GENERAL a Cuda weighs less than a 67 B-body, but options, driver weight, etc. can definately change that.
Bottom line, both cars are mid to low 14 second cars on paper, the difference would be driver weight, driver technique, traction, etc. Having owned and raced examples of both cars my money would be on the Cuda by a slight margin if the same driver made passes in each car for the best time.
