I currently have a 74 F-250 highboy with a 390 bored out to .30 over. It has an RV cam with an edelbrock intake and a holley 770 street avenger carb. I recently had it dynoed and it was making 188 HP with 260 Ft-Lb of torque at the rear wheels. It was estimated that it makes about 250 HP at the flywheel. I plan on installing headers and aluminum heads later on. In my opinion the 390 pulls real hard and with a little tweeking it can become a very impressive engine. The 460 on the other hand has the benefit of more cubic inches. I like the 390 because it bolts right in.