450 hp at the rear wheels is quite a handful to drive on the street. Actually anything over 300 will be fun and much more is not really needed for a pure street car.
Although 450 rear hp can be done with either engine, I would opt for the 351w.
A properly built 347 is certainly capable of meeting your HP goals, but you really wouldn't have any margin for error. At 450hp, the 302 block would be at the end of it's strength capability and could split unless you purchase an aftermarket block. Your goals really don't support the $2k cost of such a block.
A 351w on the other hand, will easily handle your goals in strength and durability, most are good to at least 600hp. Properly built, it will also make 450hp at a much lower RPM than the 347 and have gobs of torque at lower speeds. The 351w will fit your 67' engine bay nicely without needing an expensive set of swap headers. They are a little heavier than a 347, but still not enough to warrant the aftermarket block.
The AFR 185's would be suitable for 450hp on a base 351w. Match them with a custom cam, a Victor Jr. intake, a 750dp Holley, and a 3:50 rear gear and you will have a nice street combo with good driveability. If you want more motor, you could stroke the 351w to a 408 or a 418 and make gobs of power. In that case, you would need more head to get the most out of the engine.