I usually don't post on this board but this is definitely a subject I might be able to shed some light on. I currently own and drive (somewhat aggresively) three Hemicars. 69 B9 Mustang, solid cam T-motor. 69 SuperBee 426H 4spd. 70 Cuda 426H auto. All are stock, low milage cars and ride on repop biasbelted tires. I think the B9 is the fastest of the three but I give the edge to the Mustang largely due to it's being the lightest weight. All the cars have to be softballed off the line or they light the tires up hard. The 426H has more torque and better reponse down low and the broader powerband. The B9 is softer down low and really comes alive about 3500 and pulls harder than the 426 up top. Both motors nose over at about the same RPM but I think if the B9 had more carburetion, like the 426, it would RPM higher than the Mopar. Of course, both motors are undercammed for the airflow capacity of their respective cylinder heads and this limits the top end. So IMHO, the B9 Mustang is faster than a 426H B or E-body, but the Mopar Hemi has better street manners and overall is the more driveable motor. If both motors were in equal weight cars, it's a toss-up. Hope this helps.